private CycleLog getCurrentCycleLog() {
    if (currentIdx >= cycleLogs.size()) {
      throw new IllegalStateException("Operation not possible because there are no more compaction cycles left");
    }
    return cycleLogs.get(currentIdx);
  }
@return the {@link CycleLog} for the current compaction cycle.
ambry-store/src/main/java/com/github/ambry/store/CompactionLog.java