TracingChannel 通道
¥TracingChannel Channels
TracingChannel 是多个 diagnostics_channels 的集合，表示单个可跟踪操作的执行生命周期中的特定点。该行为分为五个 diagnostics_channels，包括 start、end、asyncStart、asyncEnd 和 error。单个可跟踪操作将在所有事件之间共享相同的事件对象，这有助于通过 weakmap 管理相关性。
¥A TracingChannel is a collection of several diagnostics_channels representing
specific points in the execution lifecycle of a single traceable action. The
behaviour is split into five diagnostics_channels consisting of start,
end, asyncStart, asyncEnd, and error. A single traceable action will
share the same event object between all events, this can be helpful for
managing correlation through a weakmap.
当任务 "completes" 时，这些事件对象将使用 result 或 error 值进行扩展。在同步任务的情况下，result 将是返回值，error 将是函数抛出的任何值。对于基于回调的异步函数，result 将是回调的第二个参数，而 error 将是 end 事件中可见的抛出错误或 asyncStart 或 asyncEnd 事件中的第一个回调参数。
¥These event objects will be extended with result or error values when
the task "completes". In the case of a synchronous task the result will be
the return value and the error will be anything thrown from the function.
With callback-based async functions the result will be the second argument
of the callback while the error will either be a thrown error visible in the
end event or the first callback argument in either of the asyncStart or
asyncEnd events.
跟踪通道应遵循以下命名模式：
¥Tracing channels should follow a naming pattern of:
-
tracing:module.class.method:start或tracing:module.function:start¥
tracing:module.class.method:startortracing:module.function:start -
tracing:module.class.method:end或tracing:module.function:end¥
tracing:module.class.method:endortracing:module.function:end -
tracing:module.class.method:asyncStart或tracing:module.function:asyncStart¥
tracing:module.class.method:asyncStartortracing:module.function:asyncStart -
tracing:module.class.method:asyncEnd或tracing:module.function:asyncEnd¥
tracing:module.class.method:asyncEndortracing:module.function:asyncEnd -
tracing:module.class.method:error或tracing:module.function:error¥
tracing:module.class.method:errorortracing:module.function:error