The value of this object determines when and if to
to generate a notification for this entry:
pathChange(0) - Generate a traceRoutePathChange
notification when the current path varies from a
previously determined path.
testFailure(1) - Generate a traceRouteTestFailed
notification when the full path to a target
can't be determined.
testCompletion(2) - Generate a traceRouteTestCompleted
notification when the path to a target has been
determined.
The value of this object defaults to zero, indicating
that none of the above options have been selected.