wp_refresh_post_lock

function wp_refresh_post_lock( $response, $data, $screen_id ) {
	if ( array_key_exists( 'wp-refresh-post-lock', $data ) ) {
		$received = $data['wp-refresh-post-lock'];
		$send     = array();

		$post_id = absint( $received['post_id'] );
		if ( ! $post_id ) {
			return $response;
		}

		if ( ! current_user_can( 'edit_post', $post_id ) ) {
			return $response;
		}

		$user_id = wp_check_post_lock( $post_id );
		$user    = get_userdata( $user_id );
		if ( $user ) {
			$error = array(
				/* translators: %s: User's display name. */
				'text' => sprintf( __( '%s has taken over and is currently editing.' ), $user->display_name ),
			);

			if ( get_option( 'show_avatars' ) ) {
				$error['avatar_src']    = get_avatar_url( $user->ID, array( 'size' => 64 ) );
				$error['avatar_src_2x'] = get_avatar_url( $user->ID, array( 'size' => 128 ) );
			}

			$send['lock_error'] = $error;
		} else {
			$new_lock = wp_set_post_lock( $post_id );
			if ( $new_lock ) {
				$send['new_lock'] = implode( ':', $new_lock );
			}
		}

		$response['wp-refresh-post-lock'] = $send;
	}

	return $response;
}