The current definition of MessageHandler::process() is as follows:

/**
 * Called every time a message comes in. Handler is responsible for responding to client.
 */
virtual void process(Message& m, AbstractMessagingPort* p) = 0;

We would like to change this contract so that the handle does not have to know about an AbstractMessagingPort. A new method might look like this:

using SendMessageFn = stdx::function<void(Message&, Session)>;

/**
 * Called every time a message comes in.  Handler is responsible for responding to client.
 */
virtual void process(Message& m, Session session, SendMessageFn reply) = 0;

Session objects would be created in PortMessageServer::handleIncomingMessage().

Some questions:

• Can we do this for mongod and mongos separately?
• What information from AbstractMessagingPort needs to go into a Session to make this work?