EventSource.SetCurrentThreadActivityId Method (Guid)
[Supported in the .NET Framework 4.5.1 and later versions]
Sets the activity ID on the current thread.
Assemblies: mscorlib (in mscorlib.dll)
System.Diagnostics.Tracing (in System.Diagnostics.Tracing.dll)
Calling the SetCurrentThreadActivityId method sets the activity ID on a per-thread basis. All events on the thread will have that activity ID until a new activity is started on the same thread.
This method is called only by libraries that manage their own threads.