Отправить сообщение программно

$chat_room = 'private:' . min( $from_user, $to_user ) . ':' . max( $from_user, $to_user );

	if ( ! rcl_get_chat_by_room( $chat_room ) ) {
		rcl_insert_chat( $chat_room, 'private' );
	}

	if ( ! class_exists( 'Rcl_Chat' ) ) {
		require_once RCL_PATH . 'add-on/rcl-chat/class-rcl-chat.php';
	}

	$chat = new Rcl_Chat( [
		'chat_status' => 'private',
		'user_id'     => $from_user,
		'office_id'   => $to_user,
		'chat_room'   => $chat_room
	] );

	$chat->add_message( $message );

Где $from_user и $to_user - ID пользователей