code: void close(boolean cleanCache) {
          if (!this.closed.getAndSet(true)) {
              // Close storage reader (and thus cancel those reads).
              if (cleanCache) {
                  this.executor.execute(() -> {
                      removeAllCacheEntries();
                      log.info("{}: Closed.", this.traceObjectId);
                  });
              } else {
                  log.info("{}: Closed (no cache cleanup).", this.traceObjectId);
              }
          }
      }
docs: Closes the SegmentAttributeIndex and optionally cleans the cache.
  
  @param cleanCache If true, the Cache will be cleaned up of all entries pertaining to this Index. If false, the
  Cache will not be touched.