DeltaBufferPolicy

Overflow behaviour for a delta buffer.

There is no backpressure to be had here, and that is a property of the source rather than of this implementation: a chain produces blocks whether or not anyone is keeping up, so the only decisions available are how much to hold and what to do when that is not enough.

Chain-sourced events must never be dropped silently — a missed Spent corrupts the subscriber's view of state permanently, and it has no way to notice. So the two options are "never drop" and "fail loudly":

• Bounded(n) — on overflow the subscription terminates with scalus.cardano.infra.ScalusBufferOverflowException, so the subscriber knows its view is untrustworthy and must resync. Default, see DeltaBufferPolicy.default.
• Unbounded — memory is the only bound. For a subscriber that would rather be killed by the OOM killer than resync.

Deliberately not offered: a bounded buffer that drops. It would turn the corruption this policy exists to prevent into the default behaviour, and the subscriber could not detect it.