gtk/window.go
func (v *Window) SetDefaultSize(width, height int) {
	C.gtk_window_set_default_size(v.native(), C.gint(width), C.gint(height))
}
func (v *Window) SetDefaultSize(width, height int) {
	C.gtk_window_set_default_size(v.native(), C.gint(width), C.gint(height))
}
// SetDefaultSize is a wrapper around gtk_window_set_default_size().