code: private void processFailedReceivedDeleted(long[] failedMap, Block[] sent) {
      synchronized (receivedAndDeletedBlockList) {
        // Blocks that do not belong to an Inode are saved for
        // retransmisions
        for (int i = sent.length - 1 ; i >= 0; i--) {
          if(!LightWeightBitSet.get(failedMap, i)){
            continue;
          }
          // Insert into retry list.
          LOG.info("Block " + sent[i] + " does not belong to any file "
              + "on namenode " + avatarnodeAddress + " Retry later.");
          receivedAndDeletedBlockList.add(0, sent[i]);
          if (!DFSUtil.isDeleted(sent[i])) {
            pendingReceivedRequests++;
          }
        }
        lastBlockReceivedFailed = AvatarDataNode.now();
      }
    }
docs: Adds blocks of incremental block report back to the
  receivedAndDeletedBlockList when the blocks are to be
  retried later (when sending to standby)
  
  @param failed