public function getSendNsca(string $connectionString, int $encryptionCipher = null, string $encryptionPassword = null): SendNsca {
        $password = $encryptionPassword ?? '';
        $cipher = $encryptionCipher ?? Ciphers::ENCRYPT_NONE;
        $key = md5($connectionString . ':' . $cipher . ':' . $password);
        if (false === isset(static::$instances[$key])) {
            static::$instances[$key] = new SendNsca($connectionString, $this->getEncryptor($cipher, $password));
        }
        return static::$instances[$key];
    }