'Pause this L{CooperativeTask}.  Stop doing work until
L{CooperativeTask.resume} is called.  If C{pause} is called more than
once, C{resume} must be called an equal number of times to resume this
task.
@raise TaskFinished: if this task has already finished or completed.'

def pause(self):

    self._checkFinish()
    self._pauseCount += 1
    if (self._pauseCount == 1):
        self._cooperator._removeTask(self)
