bp_activity_clear_new_mentions( int $user_id )

function bp_activity_clear_new_mentions( $user_id ) {
	bp_delete_user_meta( $user_id, 'bp_new_mention_count' );
	bp_delete_user_meta( $user_id, 'bp_new_mentions'      );

	/**
	 * Fires once mentions has been reset for a given user.
	 *
	 * @since BuddyPress  2.5.0
	 *
	 * @param  int $user_id The id of the user whose unread mentions are being reset.
	 */
	do_action( 'bp_activity_clear_new_mentions', $user_id );
}