code: protected Client createClient(String configServiceName)
        throws GeneralSecurityException, IOException {
      return new Client.Builder(configServiceName)
          .setStatsLogFrequency(statsLogFrequency())
          .setHttpTransport(new NetHttpTransport())
          .build();
    }
docs: A template method for constructing clients.
  
  <strong>Intended Usage</strong>
  <p>
  Subclasses of may override this method to customize how the client get's built. Note that this
  method is intended to be invoked by {@link ControlFilter#init(FilterConfig)} when the
  serviceName parameter is provided. If that parameter is missing, this function will not be
  called and the client will not be constructed.
  </p>
  
  @param configServiceName the service name to use in constructing the client
  @return a {@link Client}
  @throws GeneralSecurityException indicates that client was not created successfully
  @throws IOException indicates that the client was not created successfully