Nuclei.Communication: Endpoint connection should be verified before use.

[pvandervelde]

It is possible for an endpoint to connect and then disappear. However the communication layer does not verify the status of the endpoint before using it / presenting it to the user, thus making the user believe that the endpoint is active.

There should probably be a protocol level 'ping' message that verifies if an endpoint is still active or not.

[pvandervelde]

Won't fix this directly. Will provide a way to execute a protocol / interaction level 'ping' upon request, but there is no point in doing a 'ping' before each message because that will increase the data on the line a lot.

Issue #17 will provide the 'ping' capabilities.