bbp_get_topic_author( int $topic_id )

	function bbp_get_topic_author( $topic_id = 0 ) {
		$topic_id = bbp_get_topic_id( $topic_id );

		if ( !bbp_is_topic_anonymous( $topic_id ) ) {
			$author = get_the_author_meta( 'display_name', bbp_get_topic_author_id( $topic_id ) );
		} else {
			$author = get_post_meta( $topic_id, '_bbp_anonymous_name', true );
		}

		return apply_filters( 'bbp_get_topic_author', $author, $topic_id );
	}