code: @Override
      public RetryingRpcClient build(Client<RpcRequest, RpcResponse> delegate) {
          return new RetryingRpcClient(
                  delegate, retryStrategyWithContent(), maxTotalAttempts(),
                  responseTimeoutMillisForEachAttempt());
      }
docs: Returns a newly-created {@link RetryingRpcClient} based on the properties of this builder.