把 TCP 句柄转移到其他线程

🌐 Transferring TCP handles to other threads

一个已连接的 TCP net.Socket 可以通过在 worker_threads postMessage() 调用的 transferList 中列出它来移动到另一个线程。传输完成后，源套接字会在发送线程上被销毁（进一步使用会返回 ERR_STREAM_DESTROYED 而不是静默丢弃数据），而套接字会继续在接收线程上工作。这使得可以在一个线程上接受连接，并将它们分配到一组工作线程中，例如在工作线程之上构建类似 node:cluster 的模型。

🌐 A connected TCP net.Socket can be moved to another thread by listing it in the transferList of a worker_threads postMessage() call. After the transfer, the source socket is destroyed on the sending thread (further use fails with ERR_STREAM_DESTROYED rather than silently dropping data), and the socket continues to work on the receiving thread. This makes it possible to accept connections on one thread and distribute them across a pool of worker threads, for example to build a node:cluster-like model on top of worker threads.

这个套接字必须是新接收或新创建的 TCP 连接：它必须仍然绑定到一个活跃的句柄上，不能正在连接或已被销毁，也不能已经开始读取或有缓冲的数据。否则 postMessage() 会抛出 ERR_WORKER_HANDLE_NOT_TRANSFERABLE。只支持 TCP 套接字。

🌐 The socket must be a freshly accepted or created TCP connection: it must still be attached to a live handle, must not be connecting or destroyed, and must not have started reading or have buffered data. Otherwise postMessage() throws ERR_WORKER_HANDLE_NOT_TRANSFERABLE. Only TCP sockets are supported.

const net = require('node:net');
const { Worker } = require('node:worker_threads');

// worker.js receives `{ socket }` messages and handles each connection.
const worker = new Worker('./worker.js');

const server = net.createServer((socket) => {
  // Hand the freshly accepted connection off to the worker thread.
  worker.postMessage({ socket }, [socket]);
});
server.listen(8000); 拷贝

一个监听 net.Server 也可以用同样的方式转移，这会把监听套接字本身（以及它的待接受队列）移动到接收线程。

🌐 A listening net.Server can be transferred the same way, which moves the listening socket itself (and its pending accept queue) to the receiving thread.

一个未被采纳的 TCP BoundSocket 也可以被转移，这会移动已绑定（但尚未监听或连接）的套接字。这允许一个线程同步保留一个端口，而另一个线程由服务器或外部连接采用。管道绑定是不可转移的。转移后，源 BoundSocket 的行为就像它已经被采纳一样：address()、fd() 和 close() 会抛出 ERR_SOCKET_HANDLE_ADOPTED。

🌐 An un-adopted TCP BoundSocket can also be transferred, which moves the bound (but not yet listening or connected) socket. This allows a port to be reserved synchronously on one thread and adopted by a server or outgoing connection on another. Pipe binds are not transferable. After the transfer, the source BoundSocket behaves as if it had been adopted: address(), fd() and close() throw ERR_SOCKET_HANDLE_ADOPTED.