'message' 事件

• message <Object> | <boolean> | <number> | <string> | <null> 已解析的 JSON 对象或可序列化的原始值。
• sendHandle <net.Server> | <net.Socket> 一个 net.Server 或 net.Socket 对象，或未定义。

如果使用 IPC 通道衍生 Node.js 进程（参阅子进程和集群文档），则只要子进程收到父进程使用 childprocess.send() 发送的消息，就会触发 'message' 事件。

消息会进行序列化和解析。 生成的消息可能与最初发送的消息不同。

• message <Object> | <boolean> | <number> | <string> | <null> a parsed JSON object or a serializable primitive value.
• sendHandle <net.Server> | <net.Socket> a net.Server or net.Socket object, or undefined.

If the Node.js process is spawned with an IPC channel (see the Child Process and Cluster documentation), the 'message' event is emitted whenever a message sent by a parent process using childprocess.send() is received by the child process.

The message goes through serialization and parsing. The resulting message might not be the same as what is originally sent.