Registers a libvirt event loop implementation that is backed by the default <code>GMain</code> context.
If invoked more than once this method will be a no-op. Applications should, however, take care not to register any another non-GLib event loop with libvirt.
After invoking this method, it is mandatory to run the default GMain event loop. Typically this can be satisfied by invoking <code> gtk_main</code> or <code>g_application_run</code> in the application's main thread. Failure to run the event loop will mean no libvirt events get dispatched, and the libvirt keepalive timer will kill off libvirt connections frequently.