BP_REST_Forums_Endpoint::update_item( WP_REST_Request $request )

	public function update_item( $request ) {
		$forum = get_post( $request['id'] );

		$user_id = bbp_get_user_id( 0, true, true );

		$success = false;
		$action  = '';

		$is_subscription = bbp_is_user_subscribed( $user_id, $forum->ID );
		if ( true === $is_subscription ) {
			$success = bbp_remove_user_subscription( $user_id, $forum->ID );
			$action  = 'unsubscribe';
		} elseif ( false === $is_subscription ) {
			$success = bbp_add_user_subscription( $user_id, $forum->ID );
			$action  = 'subscribe';
		}

		// Do additional subscriptions actions.
		do_action( 'bbp_subscriptions_handler', $success, $user_id, $forum->ID, $action );

		$retval['update'] = $success;

		$retval['data'] = $this->prepare_response_for_collection(
			$this->prepare_item_for_response( $forum, $request )
		);

		$response = rest_ensure_response( $retval );

		/**
		 * Fires after a forum has been updated and fetched via the REST API.
		 *
		 * @param array            $forum    Fetched forum.
		 * @param WP_REST_Response $response The response data.
		 * @param WP_REST_Request  $request  The request sent to the API.
		 *
		 * @since 0.1.0
		 */
		do_action( 'bp_rest_forum_update_item', $forum, $response, $request );

		return $response;
	}