tracing.enable()
启用此 Tracing 对象，用于 Tracing 对象涵盖的类别集合。
【Enables this Tracing object for the set of categories covered by the
Tracing object.】
启用此 Tracing 对象，用于 Tracing 对象涵盖的类别集合。
【Enables this Tracing object for the set of categories covered by the
Tracing object.】