docs: function Parser(stream) {
    StreamStack.call(this, stream, {
      data: function(b) { this._onData(b); }
    });
    this._onData = this._parseHeader;
    this._headerParser = new HeaderParser(new Stream(), {
      emitFirstLine: false,
      strictCRLF: false,
      strictSpaceAfterColon: false,
      allowFoldedHeaders: false
    });
    this._headerParser.on('headers', this._onHeadersComplete.bind(this));
  }