The cache is for reads, not writes. There is no cache for writes.

We built our own because it needed to behave in a very specific way to meet our cost/latency goals. Running a MinIO sidecar instance means that every agent would effectively have to download every file in its entirety which would not scale well and would be expensive. We also have a pretty hard and fast rule about keeping deploying WarpStream as simple as rolling out a single stateless binary.