code: private static void buildReadRowsSettings(Builder builder, BigtableOptions options) {
      RetryOptions retryOptions = options.getRetryOptions();
      CallOptionsConfig callOptions = options.getCallOptionsConfig();
      RetrySettings.Builder retryBuilder = builder.readRowsSettings().getRetrySettings().toBuilder();
  
      //Timeout for ReadRows
      Duration rpcTimeout = ofMillis(retryOptions.getReadPartialRowTimeoutMillis());
      Duration totalTimeout = ofMillis(callOptions.isUseTimeout()
          ? callOptions.getLongRpcTimeoutMs()
          : retryOptions.getMaxElapsedBackoffMillis());
  
      retryBuilder
          .setInitialRetryDelay(ofMillis(retryOptions.getInitialBackoffMillis()))
          .setRetryDelayMultiplier(retryOptions.getBackoffMultiplier())
          .setMaxRetryDelay(ofMillis(MAX_RETRY_TIMEOUT_MS))
          .setMaxAttempts(retryOptions.getMaxScanTimeoutRetries())
          .setInitialRpcTimeout(rpcTimeout)
          .setMaxRpcTimeout(rpcTimeout)
          .setTotalTimeout(totalTimeout);
  
      builder.readRowsSettings()
          .setRetrySettings(retryBuilder.build())
          .setRetryableCodes(buildRetryCodes(options.getRetryOptions()));
    }
docs: To build BigtableDataSettings#readRowsSettings with default Retry settings.