verifyJWT method 
    
    
    
  Implementation
  @override
Future<bool> verifyJWT(String jwt) async {
  JWTDecoded decoded = decodeJWT(jwt);
  // Check the header
  if (decoded.header.alg != JWTHeader.JWT_ALG ||
      decoded.header.typ != JWTHeader.JWT_TYP) {
    throw VerifyJWTError(jwt, 'JWT must use EdDSA algorithm');
  }
  final Uint8List publicKey = decodeIss(decoded.payload.iss);
  return ed.verify(
    ed.PublicKey(publicKey),
    Uint8List.fromList(decoded.data),
    Uint8List.fromList(decoded.signature),
  );
  // final VerifyKey vKey = VerifyKey(publicKey);
  // final SignedMessage signedMessage = SignedMessage.fromList(
  //   signedMessage: Uint8List.fromList(
  //     decoded.signature,
  //   ),
  // );
  // return vKey.verify(
  //   signature: signedMessage.signature,
  //   message: Uint8List.fromList(decoded.data),
  // );
}