public static function setFdToCoId(int $fd)
    {
        $cid = self::getCoroutineId();

        self::$map[$cid] = $fd;
    }
public static function setFdToCoId(int $fd)
    {
        $cid = self::getCoroutineId();

        self::$map[$cid] = $fd;
    }
public static function setFdToCoId ( int $ fd ) { $ cid = self :: getCoroutineId ( ) ; self :: $ map [ $ cid ] = $ fd ; }
init coId to fd mapping
@param int $fd
init coId to fd mapping