If a socket connection is made but we never receive a heartbeat the player will try to restart the XMR process due to inactivity. It looks like restarting doesn't close the active socket and therefore we get a build up of open sockets at the XMR end.

Perhaps we ought to call dispose here: https://github.com/xibosignage/xibo-dotnetclient/blob/develop/Action/XmrSubscriber.cs#L286

Maybe we ought to consider assuming a successful first connection too? https://github.com/xibosignage/xibo-dotnetclient/blob/develop/Action/XmrSubscriber.cs#L45