node.js - async_hooks - 为什么没有调用/清理资源

Question

以下代码

import async_hooks from 'async_hooks'

console.log(`father: "${async_hooks.triggerAsyncId()}" - current: "${async_hooks.executionAsyncId()}"`)

const asyncHook = async_hooks.createHook({
  init(asyncId, type, triggerAsyncId, resource) {
    console.log(`creating - father: "${triggerAsyncId}" - current: "${asyncId}"`, {
      type,
      resource,
    })
  },
  destroy(asyncId) {
    console.log(`destroying - "${asyncId}"`)
  },
})

asyncHook.enable()

打印以下标准输出：

father: "0" - current: "1"
destroying - "4"
creating - father: "0" - current: "5" {
  type: 'TickObject',
  resource: {
    callback: [Function: afterWriteTick],
    args: [ [Object] ],
    [Symbol(async_id_symbol)]: 5,
    [Symbol(trigger_async_id_symbol)]: 0
  }
}
✨  Done in 2.22s.

问题：

1. 什么是“4”？
2. 什么是“TickObject”以及为什么在 Node.js 退出之前不清理“5”？
3. 与console.log异步一样，我希望 async_hooks 将永远被调用。为什么我在输出中看不到无限递归？

标签： node.jsasync-hooks