Adds a process, by PID, to the list of filtered processes.
This method adds the process with the specified ProcessId (PID) to the list of processes whose requests should be filtered (i.e., that the class should fire events for).
The ProcessId parameter specifies the PID of the process whose requests should be filtered. The value passed for this parameter must either be the PID of an existing process; or -1, which means "all processes".
The IncludeChildren parameter specifies whether requests made by the specified process's children should also be filtered.
Note: This method can only be called when Active is true.