findForcedMerges
open override fun findForcedMerges(infos: SegmentInfos?, maxNumSegments: Int, segmentsToMerge: MutableMap<SegmentCommitInfo, Boolean>?, mergeContext: MergePolicy.MergeContext?): MergePolicy.MergeSpecification?
Returns the merges necessary to merge the index down to a specified number of segments. This respects the .maxMergeSizeForForcedMerge setting. By default, and assuming maxNumSegments=1, only one segment will be left in the index, where that segment has no deletions pending nor separate norms, and it is in compound file format if the current useCompoundFile setting is true. This method returns multiple merges (mergeFactor at a time) so the MergeScheduler in use may make use of concurrency.