Module priority 

Priority-aware k-way merge. Each source carries an explicit priority integer. On key tie, the highest-priority source wins. Ties between equal priorities fall through to the source’s registration order (higher source index breaks the tie - matches the latest-source-wins shape used by dedup and tombstones).

This generalises dedup: pass (priority = source_index, ...) for the same behaviour. The reason to reach for priority is when the producer order on the wire doesn’t match the recency / authority ordering you want (e.g. an in-memory memtable should beat every on-disk SSTable level even though it was registered first).

Structs

PriorityEntry

PriorityMergeIterator

PrioritySource

A source + the priority it carries. Higher priority wins on key ties. Equal-priority ties fall through to registration order (the index in the new(...) argument list).