code: func DragSetIconPixbuf(context *gdk.DragContext, pixbuf *gdk.Pixbuf, hot_x int, hot_y int) {
  	ctx := unsafe.Pointer(context.Native())
  	pix := unsafe.Pointer(pixbuf.Native())
  	C.gtk_drag_set_icon_pixbuf((*C.GdkDragContext)(ctx), (*C.GdkPixbuf)(pix), C.gint(hot_x), C.gint(hot_y))
  }
docs: //for "drag-begin" event