private void maybeAdvanceLastChunk() throws IOException {
      while (true) {
        long nextChunkId = lastChunk.nextChunkId();
        if (nextChunkId == ChunkedAppendOnlyLog.NULL_ID) {
          return;
        }
        lastChunk = keyValuesLog.read(nextChunkId);
      }
    }
private void maybeAdvanceLastChunk()