gdkPixbufLoaderWrite will occur, so that it can free its
internal loading structures. Also, tries to parse any data that
hasn't yet been parsed; if the remaining data is partial or
corrupt, an error will be returned.  If FALSE is returned, error
will be set to an error from the GDK_PIXBUF_ERROR or G_FILE_ERROR
domains. If you're just cancelling a load rather than expecting it
to be finished, passing NULL for error to ignore it is
reasonable.gdkPixbufLoaderClose(object, .errwarn = TRUE)objectTRUE if all image data written so far was successfully
passed out via the update_area signalerrorGError, or NULL to ignore errors. [  allow-none  ]