'Stop timeouts and block further command processing while a long
operation completes.
@type d: L{Deferred <defer.Deferred>}
@param d: A deferred which triggers at the completion of a long
operation.
@rtype: L{Deferred <defer.Deferred>}
@return: A deferred which triggers after command processing resumes and
timeouts restart after the completion of a long operation.'

def _longOperation(self, d):

    timeOut = self.timeOut
    self.setTimeout(None)
    self.blocked = []
    d.addCallback(self._unblock)
    d.addCallback((lambda ign: self.setTimeout(timeOut)))
    return d
