worker.threadId
引用线程的整数标识符。
在工作线程内部，它作为 require('worker_threads').threadId 可用。
此值对于单个进程中的每个 Worker 实例都是唯一的。
An integer identifier for the referenced thread. Inside the worker thread,
it is available as require('worker_threads').threadId.
This value is unique for each Worker instance inside a single process.