title: how to attach glib signal callbacks to certain thread context
body: <p>So basically I'm coding following steps to create dbus based app. 
  1. g_bus_watch_name(callback for specific service to appear)
  2. g_signal_connect to attach to certain signals provided by service.
      g_signal_connect(proxy,"xyz", G_CALLBACK(callback), NULL);</p>
  
  <p>I want the "callback" to run under certain thread context.</p>
  
  <p>Any hints would be highly appreciated</p>