akka/dev

_onConnect() {
  debug('connected: %j', this.options);
  // setNoDelay being a no-op if the socket is not connected
  // https://github.com/nodejs/node-v0.x-archive/issues/15443#issuecomment-99660819
  // noDelay default is true, and set it again to make sure of it
  this._socket.setNoDelay(true);

  this._state = 'connect';
  this.emit('connect');

  this.on('handshake', () => this._onHandshake());
  this.on('heartbeat', () => this._onHeartbeat());

  // 先发一次握手请求，收到回执后再ready
  this._write(this._getAkkaHandshakePacket());
}

 _getAkkaHandshakePacket() {
  const req = new AkkaProtocolMessage();
  req.instruction = new AkkaControlMessage();
  req.instruction.commandType = COMMAND_TYPE.ASSOCIATE;
  req.instruction.handshakeInfo = new AkkaHandshakeInfo();
  req.instruction.handshakeInfo.origin = new AddressData();
  req.instruction.handshakeInfo.origin.system = this.id;
  req.instruction.handshakeInfo.origin.hostname = this.host;
  req.instruction.handshakeInfo.origin.port = this.port;
  req.instruction.handshakeInfo.origin.protocol = 'tcp';
  req.instruction.handshakeInfo.uid = getUid();
  return this._pack(AkkaProtocolMessage.encode(req).finish());
}