Guarantees of # publishes / # messages received per topic

[skugele]

In processes and threads that use message passing, we need to guarantee that those processes and threads operate under the following constraints:

1. Receive at most a single message from each subscribed to topic per invocation
2. Publish at most a single message to each published to topic per invocation

To do otherwise would be rude.

One idea that was discussed for achieving this would be to maintain a map for each topic, and to set a boolean value whenever a message is published or subscribed to/from that topic. If publishing or subscribing happens 2x, then return a warning or error and prevent the operation. Upon subsequent invocations of the process or thread (for example, between calls to a module's "call" method), the topic map could be cleared to enable publishing/subscribing again.

It's very important that this solution work for all types of FrameworkRunnables.