private ByteBuf getCache() {
        if (this.cache == null) {
            this.cache = ByteBufAlloc.byteBuffer(cacheSize);
        }
        return this.cache;
    }
Get the cache. If the cache is not initialized, initialize it.
Should be called under synchronized.
s3stream/src/main/java/com/automq/stream/s3/wal/util/WALCachedChannel.java