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- Optimize DateRangeIndex for better conflict resolution handling. It always
starts out with storing an IITreeSet of the value instead of special casing
storing an int for a single value. The `single value as int` optimization
should be provided via a separate API to be called periodically outside the
context of a normal request.
- Replaced `weightedIntersection` and `weightedUnion` calls with their
non-weighted version, as we didn't pass in weights.