realize

Called by users to attach the media stream to a `GdkSurface` they manage.

The stream can then access the resources of surface for its rendering purposes. In particular, media streams might want to create a `GdkGLContext` or sync to the `GdkFrameClock`.

Whoever calls this function is responsible for calling [method@Gtk.MediaStream.unrealize] before either the stream or surface get destroyed.

Multiple calls to this function may happen from different users of the video, even with the same surface. Each of these calls must be followed by its own call to [method@Gtk.MediaStream.unrealize].

It is not required to call this function to make a media stream work.

Parameters:

this	a `GtkMediaStream`
surface	a `GdkSurface`