worker.process
所有工作进程都是使用 child_process.fork() 创建，此函数返回的对象存储为 .process。在工作进程中，存储了全局的 process。
¥All workers are created using child_process.fork(), the returned object
from this function is stored as .process. In a worker, the global process
is stored.
看：子进程模块。
¥See: Child Process module.
如果 'disconnect' 事件发生在 process 并且 .exitedAfterDisconnect 不是 true，则工作进程将调用 process.exit(0)。这可以防止意外断开连接。
¥Workers will call process.exit(0) if the 'disconnect' event occurs
on process and .exitedAfterDisconnect is not true. This protects against
accidental disconnection.