Automattic / jetpack

		// even though it's messy, we implement these hooks because

		// the edit_comment hook doesn't include the data

		// so this saves us a DB read for every comment event

		foreach ( array( '', 'trackback', 'pingback' ) as $comment_type ) {

			foreach ( array( 'unapproved', 'approved' ) as $comment_status ) {

				$comment_action_name = "comment_{$comment_status}_{$comment_type}";

				add_action( $comment_action_name, $callable, 10, 2 );

			}

		}

		// listen for meta changes

		$this->init_listeners_for_meta_type( 'comment', $callable );

	public function init_before_send() {

		add_filter( 'jetpack_sync_before_send_wp_insert_comment', array( $this, 'expand_wp_insert_comment' ) );

		foreach ( array( '', 'trackback', 'pingback' ) as $comment_type ) {

			foreach ( array( 'unapproved', 'approved' ) as $comment_status ) {

				$comment_action_name = "comment_{$comment_status}_{$comment_type}";

				add_filter(

					'jetpack_sync_before_send_' . $comment_action_name,

					array(

						$this,

						'expand_wp_insert_comment',

					)

				);

			}

		}

		// full sync

		add_filter( 'jetpack_sync_before_send_jetpack_full_sync_comments', array( $this, 'expand_comment_ids' ) );