m. update

1 files changed, 1124 insertions, 0 deletions

diff --git a/together/node_modules/readable-stream/lib/_stream_readable.js b/together/node_modules/readable-stream/lib/_stream_readable.js
new file mode 100644
index 0000000..192d451
--- /dev/null
+++ b/together/node_modules/readable-stream/lib/_stream_readable.js
@@ -0,0 +1,1124 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+'use strict';
+
+module.exports = Readable;
+/*<replacement>*/
+
+var Duplex;
+/*</replacement>*/
+
+Readable.ReadableState = ReadableState;
+/*<replacement>*/
+
+var EE = require('events').EventEmitter;
+
+var EElistenerCount = function EElistenerCount(emitter, type) {
+  return emitter.listeners(type).length;
+};
+/*</replacement>*/
+
+/*<replacement>*/
+
+
+var Stream = require('./internal/streams/stream');
+/*</replacement>*/
+
+
+var Buffer = require('buffer').Buffer;
+
+var OurUint8Array = global.Uint8Array || function () {};
+
+function _uint8ArrayToBuffer(chunk) {
+  return Buffer.from(chunk);
+}
+
+function _isUint8Array(obj) {
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
+}
+/*<replacement>*/
+
+
+var debugUtil = require('util');
+
+var debug;
+
+if (debugUtil && debugUtil.debuglog) {
+  debug = debugUtil.debuglog('stream');
+} else {
+  debug = function debug() {};
+}
+/*</replacement>*/
+
+
+var BufferList = require('./internal/streams/buffer_list');
+
+var destroyImpl = require('./internal/streams/destroy');
+
+var _require = require('./internal/streams/state'),
+    getHighWaterMark = _require.getHighWaterMark;
+
+var _require$codes = require('../errors').codes,
+    ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
+    ERR_STREAM_PUSH_AFTER_EOF = _require$codes.ERR_STREAM_PUSH_AFTER_EOF,
+    ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
+    ERR_STREAM_UNSHIFT_AFTER_END_EVENT = _require$codes.ERR_STREAM_UNSHIFT_AFTER_END_EVENT; // Lazy loaded to improve the startup performance.
+
+
+var StringDecoder;
+var createReadableStreamAsyncIterator;
+var from;
+
+require('inherits')(Readable, Stream);
+
+var errorOrDestroy = destroyImpl.errorOrDestroy;
+var kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];
+
+function prependListener(emitter, event, fn) {
+  // Sadly this is not cacheable as some libraries bundle their own
+  // event emitter implementation with them.
+  if (typeof emitter.prependListener === 'function') return emitter.prependListener(event, fn); // This is a hack to make sure that our error handler is attached before any
+  // userland ones.  NEVER DO THIS. This is here only because this code needs
+  // to continue to work with older versions of Node.js that do not include
+  // the prependListener() method. The goal is to eventually remove this hack.
+
+  if (!emitter._events || !emitter._events[event]) emitter.on(event, fn);else if (Array.isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
+}
+
+function ReadableState(options, stream, isDuplex) {
+  Duplex = Duplex || require('./_stream_duplex');
+  options = options || {}; // Duplex streams are both readable and writable, but share
+  // the same options object.
+  // However, some cases require setting options to different
+  // values for the readable and the writable sides of the duplex stream.
+  // These options can be provided separately as readableXXX and writableXXX.
+
+  if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex; // object stream flag. Used to make read(n) ignore n and to
+  // make all the buffer merging and length checks go away
+
+  this.objectMode = !!options.objectMode;
+  if (isDuplex) this.objectMode = this.objectMode || !!options.readableObjectMode; // the point at which it stops calling _read() to fill the buffer
+  // Note: 0 is a valid value, means "don't call _read preemptively ever"
+
+  this.highWaterMark = getHighWaterMark(this, options, 'readableHighWaterMark', isDuplex); // A linked list is used to store data chunks instead of an array because the
+  // linked list can remove elements from the beginning faster than
+  // array.shift()
+
+  this.buffer = new BufferList();
+  this.length = 0;
+  this.pipes = null;
+  this.pipesCount = 0;
+  this.flowing = null;
+  this.ended = false;
+  this.endEmitted = false;
+  this.reading = false; // a flag to be able to tell if the event 'readable'/'data' is emitted
+  // immediately, or on a later tick.  We set this to true at first, because
+  // any actions that shouldn't happen until "later" should generally also
+  // not happen before the first read call.
+
+  this.sync = true; // whenever we return null, then we set a flag to say
+  // that we're awaiting a 'readable' event emission.
+
+  this.needReadable = false;
+  this.emittedReadable = false;
+  this.readableListening = false;
+  this.resumeScheduled = false;
+  this.paused = true; // Should close be emitted on destroy. Defaults to true.
+
+  this.emitClose = options.emitClose !== false; // Should .destroy() be called after 'end' (and potentially 'finish')
+
+  this.autoDestroy = !!options.autoDestroy; // has it been destroyed
+
+  this.destroyed = false; // Crypto is kind of old and crusty.  Historically, its default string
+  // encoding is 'binary' so we have to make this configurable.
+  // Everything else in the universe uses 'utf8', though.
+
+  this.defaultEncoding = options.defaultEncoding || 'utf8'; // the number of writers that are awaiting a drain event in .pipe()s
+
+  this.awaitDrain = 0; // if true, a maybeReadMore has been scheduled
+
+  this.readingMore = false;
+  this.decoder = null;
+  this.encoding = null;
+
+  if (options.encoding) {
+    if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+    this.decoder = new StringDecoder(options.encoding);
+    this.encoding = options.encoding;
+  }
+}
+
+function Readable(options) {
+  Duplex = Duplex || require('./_stream_duplex');
+  if (!(this instanceof Readable)) return new Readable(options); // Checking for a Stream.Duplex instance is faster here instead of inside
+  // the ReadableState constructor, at least with V8 6.5
+
+  var isDuplex = this instanceof Duplex;
+  this._readableState = new ReadableState(options, this, isDuplex); // legacy
+
+  this.readable = true;
+
+  if (options) {
+    if (typeof options.read === 'function') this._read = options.read;
+    if (typeof options.destroy === 'function') this._destroy = options.destroy;
+  }
+
+  Stream.call(this);
+}
+
+Object.defineProperty(Readable.prototype, 'destroyed', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    if (this._readableState === undefined) {
+      return false;
+    }
+
+    return this._readableState.destroyed;
+  },
+  set: function set(value) {
+    // we ignore the value if the stream
+    // has not been initialized yet
+    if (!this._readableState) {
+      return;
+    } // backward compatibility, the user is explicitly
+    // managing destroyed
+
+
+    this._readableState.destroyed = value;
+  }
+});
+Readable.prototype.destroy = destroyImpl.destroy;
+Readable.prototype._undestroy = destroyImpl.undestroy;
+
+Readable.prototype._destroy = function (err, cb) {
+  cb(err);
+}; // Manually shove something into the read() buffer.
+// This returns true if the highWaterMark has not been hit yet,
+// similar to how Writable.write() returns true if you should
+// write() some more.
+
+
+Readable.prototype.push = function (chunk, encoding) {
+  var state = this._readableState;
+  var skipChunkCheck;
+
+  if (!state.objectMode) {
+    if (typeof chunk === 'string') {
+      encoding = encoding || state.defaultEncoding;
+
+      if (encoding !== state.encoding) {
+        chunk = Buffer.from(chunk, encoding);
+        encoding = '';
+      }
+
+      skipChunkCheck = true;
+    }
+  } else {
+    skipChunkCheck = true;
+  }
+
+  return readableAddChunk(this, chunk, encoding, false, skipChunkCheck);
+}; // Unshift should *always* be something directly out of read()
+
+
+Readable.prototype.unshift = function (chunk) {
+  return readableAddChunk(this, chunk, null, true, false);
+};
+
+function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) {
+  debug('readableAddChunk', chunk);
+  var state = stream._readableState;
+
+  if (chunk === null) {
+    state.reading = false;
+    onEofChunk(stream, state);
+  } else {
+    var er;
+    if (!skipChunkCheck) er = chunkInvalid(state, chunk);
+
+    if (er) {
+      errorOrDestroy(stream, er);
+    } else if (state.objectMode || chunk && chunk.length > 0) {
+      if (typeof chunk !== 'string' && !state.objectMode && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
+        chunk = _uint8ArrayToBuffer(chunk);
+      }
+
+      if (addToFront) {
+        if (state.endEmitted) errorOrDestroy(stream, new ERR_STREAM_UNSHIFT_AFTER_END_EVENT());else addChunk(stream, state, chunk, true);
+      } else if (state.ended) {
+        errorOrDestroy(stream, new ERR_STREAM_PUSH_AFTER_EOF());
+      } else if (state.destroyed) {
+        return false;
+      } else {
+        state.reading = false;
+
+        if (state.decoder && !encoding) {
+          chunk = state.decoder.write(chunk);
+          if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);else maybeReadMore(stream, state);
+        } else {
+          addChunk(stream, state, chunk, false);
+        }
+      }
+    } else if (!addToFront) {
+      state.reading = false;
+      maybeReadMore(stream, state);
+    }
+  } // We can push more data if we are below the highWaterMark.
+  // Also, if we have no data yet, we can stand some more bytes.
+  // This is to work around cases where hwm=0, such as the repl.
+
+
+  return !state.ended && (state.length < state.highWaterMark || state.length === 0);
+}
+
+function addChunk(stream, state, chunk, addToFront) {
+  if (state.flowing && state.length === 0 && !state.sync) {
+    state.awaitDrain = 0;
+    stream.emit('data', chunk);
+  } else {
+    // update the buffer info.
+    state.length += state.objectMode ? 1 : chunk.length;
+    if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);
+    if (state.needReadable) emitReadable(stream);
+  }
+
+  maybeReadMore(stream, state);
+}
+
+function chunkInvalid(state, chunk) {
+  var er;
+
+  if (!_isUint8Array(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
+    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer', 'Uint8Array'], chunk);
+  }
+
+  return er;
+}
+
+Readable.prototype.isPaused = function () {
+  return this._readableState.flowing === false;
+}; // backwards compatibility.
+
+
+Readable.prototype.setEncoding = function (enc) {
+  if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
+  var decoder = new StringDecoder(enc);
+  this._readableState.decoder = decoder; // If setEncoding(null), decoder.encoding equals utf8
+
+  this._readableState.encoding = this._readableState.decoder.encoding; // Iterate over current buffer to convert already stored Buffers:
+
+  var p = this._readableState.buffer.head;
+  var content = '';
+
+  while (p !== null) {
+    content += decoder.write(p.data);
+    p = p.next;
+  }
+
+  this._readableState.buffer.clear();
+
+  if (content !== '') this._readableState.buffer.push(content);
+  this._readableState.length = content.length;
+  return this;
+}; // Don't raise the hwm > 1GB
+
+
+var MAX_HWM = 0x40000000;
+
+function computeNewHighWaterMark(n) {
+  if (n >= MAX_HWM) {
+    // TODO(ronag): Throw ERR_VALUE_OUT_OF_RANGE.
+    n = MAX_HWM;
+  } else {
+    // Get the next highest power of 2 to prevent increasing hwm excessively in
+    // tiny amounts
+    n--;
+    n |= n >>> 1;
+    n |= n >>> 2;
+    n |= n >>> 4;
+    n |= n >>> 8;
+    n |= n >>> 16;
+    n++;
+  }
+
+  return n;
+} // This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+
+
+function howMuchToRead(n, state) {
+  if (n <= 0 || state.length === 0 && state.ended) return 0;
+  if (state.objectMode) return 1;
+
+  if (n !== n) {
+    // Only flow one buffer at a time
+    if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
+  } // If we're asking for more than the current hwm, then raise the hwm.
+
+
+  if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
+  if (n <= state.length) return n; // Don't have enough
+
+  if (!state.ended) {
+    state.needReadable = true;
+    return 0;
+  }
+
+  return state.length;
+} // you can override either this method, or the async _read(n) below.
+
+
+Readable.prototype.read = function (n) {
+  debug('read', n);
+  n = parseInt(n, 10);
+  var state = this._readableState;
+  var nOrig = n;
+  if (n !== 0) state.emittedReadable = false; // if we're doing read(0) to trigger a readable event, but we
+  // already have a bunch of data in the buffer, then just trigger
+  // the 'readable' event and move on.
+
+  if (n === 0 && state.needReadable && ((state.highWaterMark !== 0 ? state.length >= state.highWaterMark : state.length > 0) || state.ended)) {
+    debug('read: emitReadable', state.length, state.ended);
+    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
+    return null;
+  }
+
+  n = howMuchToRead(n, state); // if we've ended, and we're now clear, then finish it up.
+
+  if (n === 0 && state.ended) {
+    if (state.length === 0) endReadable(this);
+    return null;
+  } // All the actual chunk generation logic needs to be
+  // *below* the call to _read.  The reason is that in certain
+  // synthetic stream cases, such as passthrough streams, _read
+  // may be a completely synchronous operation which may change
+  // the state of the read buffer, providing enough data when
+  // before there was *not* enough.
+  //
+  // So, the steps are:
+  // 1. Figure out what the state of things will be after we do
+  // a read from the buffer.
+  //
+  // 2. If that resulting state will trigger a _read, then call _read.
+  // Note that this may be asynchronous, or synchronous.  Yes, it is
+  // deeply ugly to write APIs this way, but that still doesn't mean
+  // that the Readable class should behave improperly, as streams are
+  // designed to be sync/async agnostic.
+  // Take note if the _read call is sync or async (ie, if the read call
+  // has returned yet), so that we know whether or not it's safe to emit
+  // 'readable' etc.
+  //
+  // 3. Actually pull the requested chunks out of the buffer and return.
+  // if we need a readable event, then we need to do some reading.
+
+
+  var doRead = state.needReadable;
+  debug('need readable', doRead); // if we currently have less than the highWaterMark, then also read some
+
+  if (state.length === 0 || state.length - n < state.highWaterMark) {
+    doRead = true;
+    debug('length less than watermark', doRead);
+  } // however, if we've ended, then there's no point, and if we're already
+  // reading, then it's unnecessary.
+
+
+  if (state.ended || state.reading) {
+    doRead = false;
+    debug('reading or ended', doRead);
+  } else if (doRead) {
+    debug('do read');
+    state.reading = true;
+    state.sync = true; // if the length is currently zero, then we *need* a readable event.
+
+    if (state.length === 0) state.needReadable = true; // call internal read method
+
+    this._read(state.highWaterMark);
+
+    state.sync = false; // If _read pushed data synchronously, then `reading` will be false,
+    // and we need to re-evaluate how much data we can return to the user.
+
+    if (!state.reading) n = howMuchToRead(nOrig, state);
+  }
+
+  var ret;
+  if (n > 0) ret = fromList(n, state);else ret = null;
+
+  if (ret === null) {
+    state.needReadable = state.length <= state.highWaterMark;
+    n = 0;
+  } else {
+    state.length -= n;
+    state.awaitDrain = 0;
+  }
+
+  if (state.length === 0) {
+    // If we have nothing in the buffer, then we want to know
+    // as soon as we *do* get something into the buffer.
+    if (!state.ended) state.needReadable = true; // If we tried to read() past the EOF, then emit end on the next tick.
+
+    if (nOrig !== n && state.ended) endReadable(this);
+  }
+
+  if (ret !== null) this.emit('data', ret);
+  return ret;
+};
+
+function onEofChunk(stream, state) {
+  debug('onEofChunk');
+  if (state.ended) return;
+
+  if (state.decoder) {
+    var chunk = state.decoder.end();
+
+    if (chunk && chunk.length) {
+      state.buffer.push(chunk);
+      state.length += state.objectMode ? 1 : chunk.length;
+    }
+  }
+
+  state.ended = true;
+
+  if (state.sync) {
+    // if we are sync, wait until next tick to emit the data.
+    // Otherwise we risk emitting data in the flow()
+    // the readable code triggers during a read() call
+    emitReadable(stream);
+  } else {
+    // emit 'readable' now to make sure it gets picked up.
+    state.needReadable = false;
+
+    if (!state.emittedReadable) {
+      state.emittedReadable = true;
+      emitReadable_(stream);
+    }
+  }
+} // Don't emit readable right away in sync mode, because this can trigger
+// another read() call => stack overflow.  This way, it might trigger
+// a nextTick recursion warning, but that's not so bad.
+
+
+function emitReadable(stream) {
+  var state = stream._readableState;
+  debug('emitReadable', state.needReadable, state.emittedReadable);
+  state.needReadable = false;
+
+  if (!state.emittedReadable) {
+    debug('emitReadable', state.flowing);
+    state.emittedReadable = true;
+    process.nextTick(emitReadable_, stream);
+  }
+}
+
+function emitReadable_(stream) {
+  var state = stream._readableState;
+  debug('emitReadable_', state.destroyed, state.length, state.ended);
+
+  if (!state.destroyed && (state.length || state.ended)) {
+    stream.emit('readable');
+    state.emittedReadable = false;
+  } // The stream needs another readable event if
+  // 1. It is not flowing, as the flow mechanism will take
+  //    care of it.
+  // 2. It is not ended.
+  // 3. It is below the highWaterMark, so we can schedule
+  //    another readable later.
+
+
+  state.needReadable = !state.flowing && !state.ended && state.length <= state.highWaterMark;
+  flow(stream);
+} // at this point, the user has presumably seen the 'readable' event,
+// and called read() to consume some data.  that may have triggered
+// in turn another _read(n) call, in which case reading = true if
+// it's in progress.
+// However, if we're not ended, or reading, and the length < hwm,
+// then go ahead and try to read some more preemptively.
+
+
+function maybeReadMore(stream, state) {
+  if (!state.readingMore) {
+    state.readingMore = true;
+    process.nextTick(maybeReadMore_, stream, state);
+  }
+}
+
+function maybeReadMore_(stream, state) {
+  // Attempt to read more data if we should.
+  //
+  // The conditions for reading more data are (one of):
+  // - Not enough data buffered (state.length < state.highWaterMark). The loop
+  //   is responsible for filling the buffer with enough data if such data
+  //   is available. If highWaterMark is 0 and we are not in the flowing mode
+  //   we should _not_ attempt to buffer any extra data. We'll get more data
+  //   when the stream consumer calls read() instead.
+  // - No data in the buffer, and the stream is in flowing mode. In this mode
+  //   the loop below is responsible for ensuring read() is called. Failing to
+  //   call read here would abort the flow and there's no other mechanism for
+  //   continuing the flow if the stream consumer has just subscribed to the
+  //   'data' event.
+  //
+  // In addition to the above conditions to keep reading data, the following
+  // conditions prevent the data from being read:
+  // - The stream has ended (state.ended).
+  // - There is already a pending 'read' operation (state.reading). This is a
+  //   case where the the stream has called the implementation defined _read()
+  //   method, but they are processing the call asynchronously and have _not_
+  //   called push() with new data. In this case we skip performing more
+  //   read()s. The execution ends in this method again after the _read() ends
+  //   up calling push() with more data.
+  while (!state.reading && !state.ended && (state.length < state.highWaterMark || state.flowing && state.length === 0)) {
+    var len = state.length;
+    debug('maybeReadMore read 0');
+    stream.read(0);
+    if (len === state.length) // didn't get any data, stop spinning.
+      break;
+  }
+
+  state.readingMore = false;
+} // abstract method.  to be overridden in specific implementation classes.
+// call cb(er, data) where data is <= n in length.
+// for virtual (non-string, non-buffer) streams, "length" is somewhat
+// arbitrary, and perhaps not very meaningful.
+
+
+Readable.prototype._read = function (n) {
+  errorOrDestroy(this, new ERR_METHOD_NOT_IMPLEMENTED('_read()'));
+};
+
+Readable.prototype.pipe = function (dest, pipeOpts) {
+  var src = this;
+  var state = this._readableState;
+
+  switch (state.pipesCount) {
+    case 0:
+      state.pipes = dest;
+      break;
+
+    case 1:
+      state.pipes = [state.pipes, dest];
+      break;
+
+    default:
+      state.pipes.push(dest);
+      break;
+  }
+
+  state.pipesCount += 1;
+  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);
+  var doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;
+  var endFn = doEnd ? onend : unpipe;
+  if (state.endEmitted) process.nextTick(endFn);else src.once('end', endFn);
+  dest.on('unpipe', onunpipe);
+
+  function onunpipe(readable, unpipeInfo) {
+    debug('onunpipe');
+
+    if (readable === src) {
+      if (unpipeInfo && unpipeInfo.hasUnpiped === false) {
+        unpipeInfo.hasUnpiped = true;
+        cleanup();
+      }
+    }
+  }
+
+  function onend() {
+    debug('onend');
+    dest.end();
+  } // when the dest drains, it reduces the awaitDrain counter
+  // on the source.  This would be more elegant with a .once()
+  // handler in flow(), but adding and removing repeatedly is
+  // too slow.
+
+
+  var ondrain = pipeOnDrain(src);
+  dest.on('drain', ondrain);
+  var cleanedUp = false;
+
+  function cleanup() {
+    debug('cleanup'); // cleanup event handlers once the pipe is broken
+
+    dest.removeListener('close', onclose);
+    dest.removeListener('finish', onfinish);
+    dest.removeListener('drain', ondrain);
+    dest.removeListener('error', onerror);
+    dest.removeListener('unpipe', onunpipe);
+    src.removeListener('end', onend);
+    src.removeListener('end', unpipe);
+    src.removeListener('data', ondata);
+    cleanedUp = true; // if the reader is waiting for a drain event from this
+    // specific writer, then it would cause it to never start
+    // flowing again.
+    // So, if this is awaiting a drain, then we just call it now.
+    // If we don't know, then assume that we are waiting for one.
+
+    if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
+  }
+
+  src.on('data', ondata);
+
+  function ondata(chunk) {
+    debug('ondata');
+    var ret = dest.write(chunk);
+    debug('dest.write', ret);
+
+    if (ret === false) {
+      // If the user unpiped during `dest.write()`, it is possible
+      // to get stuck in a permanently paused state if that write
+      // also returned false.
+      // => Check whether `dest` is still a piping destination.
+      if ((state.pipesCount === 1 && state.pipes === dest || state.pipesCount > 1 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
+        debug('false write response, pause', state.awaitDrain);
+        state.awaitDrain++;
+      }
+
+      src.pause();
+    }
+  } // if the dest has an error, then stop piping into it.
+  // however, don't suppress the throwing behavior for this.
+
+
+  function onerror(er) {
+    debug('onerror', er);
+    unpipe();
+    dest.removeListener('error', onerror);
+    if (EElistenerCount(dest, 'error') === 0) errorOrDestroy(dest, er);
+  } // Make sure our error handler is attached before userland ones.
+
+
+  prependListener(dest, 'error', onerror); // Both close and finish should trigger unpipe, but only once.
+
+  function onclose() {
+    dest.removeListener('finish', onfinish);
+    unpipe();
+  }
+
+  dest.once('close', onclose);
+
+  function onfinish() {
+    debug('onfinish');
+    dest.removeListener('close', onclose);
+    unpipe();
+  }
+
+  dest.once('finish', onfinish);
+
+  function unpipe() {
+    debug('unpipe');
+    src.unpipe(dest);
+  } // tell the dest that it's being piped to
+
+
+  dest.emit('pipe', src); // start the flow if it hasn't been started already.
+
+  if (!state.flowing) {
+    debug('pipe resume');
+    src.resume();
+  }
+
+  return dest;
+};
+
+function pipeOnDrain(src) {
+  return function pipeOnDrainFunctionResult() {
+    var state = src._readableState;
+    debug('pipeOnDrain', state.awaitDrain);
+    if (state.awaitDrain) state.awaitDrain--;
+
+    if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
+      state.flowing = true;
+      flow(src);
+    }
+  };
+}
+
+Readable.prototype.unpipe = function (dest) {
+  var state = this._readableState;
+  var unpipeInfo = {
+    hasUnpiped: false
+  }; // if we're not piping anywhere, then do nothing.
+
+  if (state.pipesCount === 0) return this; // just one destination.  most common case.
+
+  if (state.pipesCount === 1) {
+    // passed in one, but it's not the right one.
+    if (dest && dest !== state.pipes) return this;
+    if (!dest) dest = state.pipes; // got a match.
+
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+    if (dest) dest.emit('unpipe', this, unpipeInfo);
+    return this;
+  } // slow case. multiple pipe destinations.
+
+
+  if (!dest) {
+    // remove all.
+    var dests = state.pipes;
+    var len = state.pipesCount;
+    state.pipes = null;
+    state.pipesCount = 0;
+    state.flowing = false;
+
+    for (var i = 0; i < len; i++) {
+      dests[i].emit('unpipe', this, {
+        hasUnpiped: false
+      });
+    }
+
+    return this;
+  } // try to find the right one.
+
+
+  var index = indexOf(state.pipes, dest);
+  if (index === -1) return this;
+  state.pipes.splice(index, 1);
+  state.pipesCount -= 1;
+  if (state.pipesCount === 1) state.pipes = state.pipes[0];
+  dest.emit('unpipe', this, unpipeInfo);
+  return this;
+}; // set up data events if they are asked for
+// Ensure readable listeners eventually get something
+
+
+Readable.prototype.on = function (ev, fn) {
+  var res = Stream.prototype.on.call(this, ev, fn);
+  var state = this._readableState;
+
+  if (ev === 'data') {
+    // update readableListening so that resume() may be a no-op
+    // a few lines down. This is needed to support once('readable').
+    state.readableListening = this.listenerCount('readable') > 0; // Try start flowing on next tick if stream isn't explicitly paused
+
+    if (state.flowing !== false) this.resume();
+  } else if (ev === 'readable') {
+    if (!state.endEmitted && !state.readableListening) {
+      state.readableListening = state.needReadable = true;
+      state.flowing = false;
+      state.emittedReadable = false;
+      debug('on readable', state.length, state.reading);
+
+      if (state.length) {
+        emitReadable(this);
+      } else if (!state.reading) {
+        process.nextTick(nReadingNextTick, this);
+      }
+    }
+  }
+
+  return res;
+};
+
+Readable.prototype.addListener = Readable.prototype.on;
+
+Readable.prototype.removeListener = function (ev, fn) {
+  var res = Stream.prototype.removeListener.call(this, ev, fn);
+
+  if (ev === 'readable') {
+    // We need to check if there is someone still listening to
+    // readable and reset the state. However this needs to happen
+    // after readable has been emitted but before I/O (nextTick) to
+    // support once('readable', fn) cycles. This means that calling
+    // resume within the same tick will have no
+    // effect.
+    process.nextTick(updateReadableListening, this);
+  }
+
+  return res;
+};
+
+Readable.prototype.removeAllListeners = function (ev) {
+  var res = Stream.prototype.removeAllListeners.apply(this, arguments);
+
+  if (ev === 'readable' || ev === undefined) {
+    // We need to check if there is someone still listening to
+    // readable and reset the state. However this needs to happen
+    // after readable has been emitted but before I/O (nextTick) to
+    // support once('readable', fn) cycles. This means that calling
+    // resume within the same tick will have no
+    // effect.
+    process.nextTick(updateReadableListening, this);
+  }
+
+  return res;
+};
+
+function updateReadableListening(self) {
+  var state = self._readableState;
+  state.readableListening = self.listenerCount('readable') > 0;
+
+  if (state.resumeScheduled && !state.paused) {
+    // flowing needs to be set to true now, otherwise
+    // the upcoming resume will not flow.
+    state.flowing = true; // crude way to check if we should resume
+  } else if (self.listenerCount('data') > 0) {
+    self.resume();
+  }
+}
+
+function nReadingNextTick(self) {
+  debug('readable nexttick read 0');
+  self.read(0);
+} // pause() and resume() are remnants of the legacy readable stream API
+// If the user uses them, then switch into old mode.
+
+
+Readable.prototype.resume = function () {
+  var state = this._readableState;
+
+  if (!state.flowing) {
+    debug('resume'); // we flow only if there is no one listening
+    // for readable, but we still have to call
+    // resume()
+
+    state.flowing = !state.readableListening;
+    resume(this, state);
+  }
+
+  state.paused = false;
+  return this;
+};
+
+function resume(stream, state) {
+  if (!state.resumeScheduled) {
+    state.resumeScheduled = true;
+    process.nextTick(resume_, stream, state);
+  }
+}
+
+function resume_(stream, state) {
+  debug('resume', state.reading);
+
+  if (!state.reading) {
+    stream.read(0);
+  }
+
+  state.resumeScheduled = false;
+  stream.emit('resume');
+  flow(stream);
+  if (state.flowing && !state.reading) stream.read(0);
+}
+
+Readable.prototype.pause = function () {
+  debug('call pause flowing=%j', this._readableState.flowing);
+
+  if (this._readableState.flowing !== false) {
+    debug('pause');
+    this._readableState.flowing = false;
+    this.emit('pause');
+  }
+
+  this._readableState.paused = true;
+  return this;
+};
+
+function flow(stream) {
+  var state = stream._readableState;
+  debug('flow', state.flowing);
+
+  while (state.flowing && stream.read() !== null) {
+    ;
+  }
+} // wrap an old-style stream as the async data source.
+// This is *not* part of the readable stream interface.
+// It is an ugly unfortunate mess of history.
+
+
+Readable.prototype.wrap = function (stream) {
+  var _this = this;
+
+  var state = this._readableState;
+  var paused = false;
+  stream.on('end', function () {
+    debug('wrapped end');
+
+    if (state.decoder && !state.ended) {
+      var chunk = state.decoder.end();
+      if (chunk && chunk.length) _this.push(chunk);
+    }
+
+    _this.push(null);
+  });
+  stream.on('data', function (chunk) {
+    debug('wrapped data');
+    if (state.decoder) chunk = state.decoder.write(chunk); // don't skip over falsy values in objectMode
+
+    if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;
+
+    var ret = _this.push(chunk);
+
+    if (!ret) {
+      paused = true;
+      stream.pause();
+    }
+  }); // proxy all the other methods.
+  // important when wrapping filters and duplexes.
+
+  for (var i in stream) {
+    if (this[i] === undefined && typeof stream[i] === 'function') {
+      this[i] = function methodWrap(method) {
+        return function methodWrapReturnFunction() {
+          return stream[method].apply(stream, arguments);
+        };
+      }(i);
+    }
+  } // proxy certain important events.
+
+
+  for (var n = 0; n < kProxyEvents.length; n++) {
+    stream.on(kProxyEvents[n], this.emit.bind(this, kProxyEvents[n]));
+  } // when we try to consume some more bytes, simply unpause the
+  // underlying stream.
+
+
+  this._read = function (n) {
+    debug('wrapped _read', n);
+
+    if (paused) {
+      paused = false;
+      stream.resume();
+    }
+  };
+
+  return this;
+};
+
+if (typeof Symbol === 'function') {
+  Readable.prototype[Symbol.asyncIterator] = function () {
+    if (createReadableStreamAsyncIterator === undefined) {
+      createReadableStreamAsyncIterator = require('./internal/streams/async_iterator');
+    }
+
+    return createReadableStreamAsyncIterator(this);
+  };
+}
+
+Object.defineProperty(Readable.prototype, 'readableHighWaterMark', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.highWaterMark;
+  }
+});
+Object.defineProperty(Readable.prototype, 'readableBuffer', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState && this._readableState.buffer;
+  }
+});
+Object.defineProperty(Readable.prototype, 'readableFlowing', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.flowing;
+  },
+  set: function set(state) {
+    if (this._readableState) {
+      this._readableState.flowing = state;
+    }
+  }
+}); // exposed for testing purposes only.
+
+Readable._fromList = fromList;
+Object.defineProperty(Readable.prototype, 'readableLength', {
+  // making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get: function get() {
+    return this._readableState.length;
+  }
+}); // Pluck off n bytes from an array of buffers.
+// Length is the combined lengths of all the buffers in the list.
+// This function is designed to be inlinable, so please take care when making
+// changes to the function body.
+
+function fromList(n, state) {
+  // nothing buffered
+  if (state.length === 0) return null;
+  var ret;
+  if (state.objectMode) ret = state.buffer.shift();else if (!n || n >= state.length) {
+    // read it all, truncate the list
+    if (state.decoder) ret = state.buffer.join('');else if (state.buffer.length === 1) ret = state.buffer.first();else ret = state.buffer.concat(state.length);
+    state.buffer.clear();
+  } else {
+    // read part of list
+    ret = state.buffer.consume(n, state.decoder);
+  }
+  return ret;
+}
+
+function endReadable(stream) {
+  var state = stream._readableState;
+  debug('endReadable', state.endEmitted);
+
+  if (!state.endEmitted) {
+    state.ended = true;
+    process.nextTick(endReadableNT, state, stream);
+  }
+}
+
+function endReadableNT(state, stream) {
+  debug('endReadableNT', state.endEmitted, state.length); // Check that we didn't get one last unshift.
+
+  if (!state.endEmitted && state.length === 0) {
+    state.endEmitted = true;
+    stream.readable = false;
+    stream.emit('end');
+
+    if (state.autoDestroy) {
+      // In case of duplex streams we need a way to detect
+      // if the writable side is ready for autoDestroy as well
+      var wState = stream._writableState;
+
+      if (!wState || wState.autoDestroy && wState.finished) {
+        stream.destroy();
+      }
+    }
+  }
+}
+
+if (typeof Symbol === 'function') {
+  Readable.from = function (iterable, opts) {
+    if (from === undefined) {
+      from = require('./internal/streams/from');
+    }
+
+    return from(Readable, iterable, opts);
+  };
+}
+
+function indexOf(xs, x) {
+  for (var i = 0, l = xs.length; i < l; i++) {
+    if (xs[i] === x) return i;
+  }
+
+  return -1;
+}
\ No newline at end of file