'Close all persistent connections and remove them from the pool.
@return: L{defer.Deferred} that fires when all connections have been
closed.'

def closeCachedConnections(self):

    results = []
    for protocols in itervalues(self._connections):
        for p in protocols:
            results.append(p.abort())
    self._connections = {}
    for dc in itervalues(self._timeouts):
        dc.cancel()
    self._timeouts = {}
    return defer.gatherResults(results).addCallback((lambda ign: None))
