code: def queueMessage(self, sender, target, value,
                       consequence=None):
          
          self.messageCounter += 1
          _QueuedMessage.create(store=self.store,
                                sender=sender,
                                target=target,
                                value=value,
                                messageID=self.messageCounter,
                                consequence=consequence)
          self._scheduleMePlease()
docs: Queue a persistent outgoing message.
  
          @param sender: The a description of the shared item that is the sender
          of the message.
          @type sender: L{xmantissa.sharing.Identifier}
  
          @param target: The a description of the shared item that is the target
          of the message.
          @type target: L{xmantissa.sharing.Identifier}
  
          @param consequence: an item stored in the same database as this
          L{MessageQueue} implementing L{IDeliveryConsequence}.