FredPluginFCPServer: JavaDoc the message handling function to point to the new mechanism of PluginRespirator.getPluginClientByID() which allows the server to query the node for an existing client after having exited the message handler
- This allows us to tighten the constraints of what the message handler may do: Since the server plugin can send replies in the future in another thread by querying for the client by ID, we now forbid the message handling function to execute for a long time.
- Also, we strongly stress in the JavaDoc that the mechanism of getting a client by ID in the future is not optional by explaining why referemces to FCPPluginClient objects must not be kept in memory