OptionalendBlock end timestamp (ISO 8601). Only consulted when start is
nullish; the amount is otherwise derived from start alone so
consecutive queries against the same block return the same
amount.
OptionalstartBlock start timestamp (ISO 8601). Optional — falls back to a
simple hash of end when only the closing edge is available.
When both are nullish, returns 0.
Options accepted by getDemoBlockRaised.