A Compactor records suggested compactions and periodically makes requests to the engine to reclaim storage space.
NewCompactor returns a compactor for the specified storage engine.
Start launches a compaction processing goroutine and exits when the provided stopper indicates. Processing is done with a periodicity of compactionMinInterval, but only if there are compactions pending.
Suggest writes the specified compaction to persistent storage and pings the processing goroutine.
Metrics holds all metrics relating to a Compactor.
MetricStruct implements the metrics.Struct interface.