code: func (c *Cluster) getEntriesGroupByRegions(mvccStore MVCCStore, start, end MvccKey, count int) [][]Pair {
  	startTS := uint64(math.MaxUint64)
  	limit := int(math.MaxInt32)
  	pairs := mvccStore.Scan(start.Raw(), end.Raw(), limit, startTS, kvrpcpb.IsolationLevel_SI)
  	regionEntriesSlice := make([][]Pair, 0, count)
  	quotient := len(pairs) / count
  	remainder := len(pairs) % count
  	i := 0
  	for i < len(pairs) {
  		regionEntryCount := quotient
  		if remainder > 0 {
  			remainder--
  			regionEntryCount++
  		}
  		regionEntries := pairs[i : i+regionEntryCount]
  		regionEntriesSlice = append(regionEntriesSlice, regionEntries)
  		i += regionEntryCount
  	}
  	return regionEntriesSlice
  }
docs: // getEntriesGroupByRegions groups the key value pairs into splitted regions.