JavaScript是单线程的。这意味着无论事件，超时或延迟使用nextTick，任何完成的计算都将阻止整个过程。

JavaScript is single-threaded. That means that regardless of events, timeouts, or delaying with nextTick, any computation done will block the whole process.

如果使用 process.nextTick ，就像它在客户端使用 setTimeout（fn，0）一样，以避免阻止UI，你可以传播你的工作量在较长的时间跨度内，为其他功能提供了一些空间。

If you split your processing in steps using process.nextTick, like it's done with setTimeout(fn, 0) on the client-side to avoid blocking the UI, you could spread your workload over a longer time span, giving some room for other functions to run.

但这是一个非常无用的解决方案 - 总工作量是相同的，分布在所有周期（使每个请求稍慢）。在实践中，任何预计需要花费超过几毫秒的计算都应该卸载到不同的进程中。为了最大化并发性，您应该始终尽快返回事件循环。

But that's a very innefective solution - the total amount of work is the same, distributed among all cycles (making each request a little slower). In practice, any kind of computation that is expected to take more than a few milliseconds should be offloaded to a different process. To maximize concurrency you should always return to the event loop as quickly as possible.

child_process.fork（）添加到v0.5。它简化了子进程的创建和通信 - 不仅仅是Web worker API，而是关闭，请参阅 URL
https://github.com/joyent /node/blob/master/doc/api/child_process.markdown 。