docs: def connectionLost(self, reason):
          """
          Inform the associated L{conncache.ConnectionCache} that this
          protocol has been disconnected.
          """
          self.nexus.conns.connectionLostForKey((endpoint.Q2QEndpoint(
                  self.nexus.svc,
                  self.nexus.addr,
                  self.transport.getQ2QPeer(),
                  PROTOCOL_NAME), None))
          AMP.connectionLost(self, reason)