Core native User Interface support. This API uses native WIN32 API on Windows,
Carbon API on OSX, and GTK2 on Linux.
Tells if the current thread is the main loop thread or not. The main loop thread is the one
in which the first "ui" library primitive has been loaded.
Starts the native UI event loop. This method can only be called from the main thread.
Stop the native UI event loop. This method can only be called from the main thread.
void ui_sync(callb : ((void -> void)))
Queue a method call callb to be executed by the main thread while running the UI event
loop. This can be used to perform UI updates in the UI thread using results processed by