public ShutdownableThread cleanerThread() {
        return cleanerThread;
    }
Creates RemoteIndexCache with the given configs.

@param maxSize              maximum bytes size of segment index entries to be cached.
@param remoteStorageManager RemoteStorageManager instance, to be used in fetching indexes.
@param logDir               log directory
storage/src/main/java/org/apache/kafka/storage/internals/log/RemoteIndexCache.java