code: protected long loadEdits(Iterable<EditLogInputStream> editStreams) 
        throws IOException {
  
      long lastAppliedTxId = storage.getMostRecentCheckpointTxId();
      int numLoaded = 0;
      FSEditLogLoader loader = new FSEditLogLoader(namesystem);
        
      // Load latest edits
      for (EditLogInputStream editIn : editStreams) {
        FLOG.info("Load Image: Reading edits: " + editIn + " last applied txid#: "
            + lastAppliedTxId);
        numLoaded += loader.loadFSEdits(editIn, lastAppliedTxId);  
        lastAppliedTxId = loader.getLastAppliedTxId();
      }
      editLog.setLastWrittenTxId(lastAppliedTxId);
      FLOG.info("Load Image: Number of edit transactions loaded: "
          + numLoaded + " last applied txid: " + lastAppliedTxId);
  
      // update the counts
      namesystem.dir.updateCountForINodeWithQuota();    
      return numLoaded;
    }
docs: Load the specified list of edit files into the image.
  @return the txid of the current transaction (next to be loaded