docs: @Override
      protected int runTask(long ssl) {
          try {
              callback.handle(ssl, keyTypeBytes, asn1DerEncodedPrincipals);
              return 1;
          } catch (Exception e) {
              // Just catch the exception and return 0 to fail the handshake.
              // The problem is that rethrowing here is really "useless" as we will process it as part of an openssl
              // c callback which needs to return 0 for an error to abort the handshake.
              return 0;
          }
      }