Code review comment for lp:~robertcarr/mir/implement-client-credentials

The fd does make sense to be in the .proto because it is set in the message, it just happens to not be encoded with protocol buffers. However the client never sets the pid, it is implicit so it should not be represented in the protocol.

You should pass the PID (and any other required information) in the callback, i.e.:

286 + (display_server.get()->*function)(
287 + 0,
288 + &parameter_message,
289 + &result_message,
290 + callback.get());

This seems like a bad use of an exception but I won't block on it.