get_context_busy_watcher

the NMClient instance.

a GObject that stays alive as long as there are pending D-Bus operations.

NMClient will schedule asynchronous D-Bus requests which will complete on the GMainContext associated with the instance. When destroying the NMClient instance, those requests are cancelled right away, however their pending requests are still outstanding and queued in the GMainContext. These outstanding callbacks keep the GMainContext alive. In order to fully release all resources, the user must keep iterating the main context until all these callbacks are handled. Of course, at this point no more actual callbacks will be invoked for the user, those are all cancelled internally.

This just leaves one problem: how long does the user need to keep the GMainContext running to ensure everything is cleaned up? The answer is this GObject. Subscribe a weak reference to the returned object and keep iterating the main context until the object got unreferenced.

Note that after the NMClient instance gets destroyed, all outstanding operations will be cancelled right away. That means, the user needs to iterate the MainContext a bit longer, but it is guaranteed that the cleanup happens soon after.

The way of using the context-busy-watch, is by registering a weak pointer to see when it gets destroyed. That means, user code should not take additional references on this object to not keep it alive longer.

If you plan to exit the program after releasing the NMClient instance you may not need to worry about these "leaks". Also, if you anyway plan to continue iterating the MainContext afterwards, then you don't need to care when exactly NMClient is gone completely.