Handler for high priority commands

[sigrlami]

There are occasions when we need the event loop to address particular requests.
For example, in certain scenarios like the one presented by library users, it becomes necessary for the event loop to suspend data transmission until a resume command is issued.

Relying solely on the user channel for this purpose may result in delays. Therefore, incorporating a new channel called tx or up into the GlazeClient or GlMqttClient for managing these special requests would significantly enhance the system's responsiveness and effectiveness.