@Override
 public String toString() {
   final StringBuilder sb = new StringBuilder();
   sb.append("ExtensionDescriptor");
   sb.append("{bytes=").append(bytes == null ? "null" : Hex.encodeHex(bytes));
   sb.append('}');
   return sb.toString();
 }
 @Override
 public String toString() {
   final StringBuilder sb = new StringBuilder();
   sb.append("ExtensionDescriptor");
   sb.append("tag=").append(tag);
   sb.append(",bytes=").append(Hex.encodeHex(data.array()));
   sb.append('}');
   return sb.toString();
 }