docs: private List<FailedBatch> writeOneBatch(
              StringListMap<WriteRequest> batch,
              BatchWriteRetryStrategy batchWriteRetryStrategy) {
  
          List<FailedBatch> failedBatches = new LinkedList<FailedBatch>();
          FailedBatch failedBatch = doBatchWriteItemWithRetry(batch, batchWriteRetryStrategy);
  
          if (failedBatch != null) {
              // If the exception is request entity too large, we divide the batch
              // into smaller parts.
  
              if (failedBatch.isRequestEntityTooLarge()) {
  
                  // If only one item left, the item size must beyond 64k, which
                  // exceedes the limit.
  
                  if (failedBatch.size() == 1) {
                      failedBatches.add(failedBatch);
                  } else {
                      for (final StringListMap<WriteRequest> subBatch : batch.subMaps(2, false)) {
                          failedBatches.addAll(writeOneBatch(subBatch, batchWriteRetryStrategy));
                      }
                  }
  
              } else {
                  failedBatches.add(failedBatch);
              }
  
          }
          return failedBatches;
      }