隐式的绑定

如果域正在使用中，则所有新的 EventEmitter 对象（包括流对象、请求、响应等）将在创建时隐式地绑定到活动域。

此外，传给低层事件循环请求的回调（例如 fs.open()、或其他回调接受的方法）将自动绑定到活动域。 如果它们抛出，则域将捕获错误。

为了防止过多的内存使用，Domain 对象本身没有被隐式地添加为活动域的子域。 如果是这样，则阻止请求和响应对象被正确地垃圾收集就太容易了。

要将 Domain 对象嵌套为父 Domain 的子对象，则必须显式地添加它们。

隐式的绑定路由向 Domain 的 'error' 事件抛出错误和 'error' 事件，但没有在 Domain 上注册 EventEmitter。 隐式的绑定只处理抛出的错误和 'error' 事件。

If domains are in use, then all new EventEmitter objects (including Stream objects, requests, responses, etc.) will be implicitly bound to the active domain at the time of their creation.

Additionally, callbacks passed to lowlevel event loop requests (such as to fs.open(), or other callback-taking methods) will automatically be bound to the active domain. If they throw, then the domain will catch the error.

In order to prevent excessive memory usage, Domain objects themselves are not implicitly added as children of the active domain. If they were, then it would be too easy to prevent request and response objects from being properly garbage collected.

To nest Domain objects as children of a parent Domain they must be explicitly added.

Implicit binding routes thrown errors and 'error' events to the Domain's 'error' event, but does not register the EventEmitter on the Domain. Implicit binding only takes care of thrown errors and 'error' events.