This tracing sample:
throws an exception upon execution. To see it, you have to disable the “Enable Just My Code” debugging option as well as have all Common Language Runtime Exceptions enabled in the Exception Settings dialog.
The issue is that the same Activity is started twice, first in MessageTracing.cs at line 44 and again in NserviceBusTracingListener.cs at line 32. It seems to be a benign error but does indicate that the there is no need to start the activity twice.