'A private constructor: to create a new L{CooperativeTask}, see
L{Cooperator.cooperate}.'

def __init__(self, iterator, cooperator):

    self._iterator = iterator
    self._cooperator = cooperator
    self._deferreds = []
    self._pauseCount = 0
    self._completionState = None
    self._completionResult = None
    cooperator._addTask(self)
