viewer may not see previously updated running/closed state on local queue

The client keeps a local queue for messages as they arrive. Most of the methods in the class synchronize around various state governing the behaviour ot the queue, such as whether it is 'running' or 'closed'. It is possible to view this state via isClosed() and isRunning() methods, hopwever these do not synchronise in the same way, meaning one thread (e.g the app thread) viewing these states may not see a previous update by another thread (e.g the client).

These methods are only used in a couple of places, and reading a stale value will typically only lead to further use of the queue (using methods which are synchronized around the state), so this shouldnt really cause significant issue, but it would be better to ensure the updates are seen promptly.