code: public void callRpcChecked(S request, RpcResponseHandler<? extends T> responseHandler) throws IOException {
          callRpcChecked(request, responseHandler, chooseIP(request.getIpKey()));
      }
docs: Convenience wrapper for NFS RPC calls where the IP is determined by a
  byte[] key. This method just determines the IP address and calls the
  basic method.
  
  @param request
  The request to send.
  @param responseHandler
  A response handler.
  @throws IOException