public Map<Region, List<CASEntry>> findRegionsByCASEntries(final List<CASEntry> casEntries) {
        Requires.requireNonNull(casEntries, "casEntries");
        final Map<Region, List<CASEntry>> regionMap = Maps.newHashMap();
        final StampedLock stampedLock = this.stampedLock;
        final long stamp = stampedLock.readLock();
        try {
            for (final CASEntry casEntry : casEntries) {
                final Region region = findRegionByKeyWithoutLock(casEntry.getKey());
                regionMap.computeIfAbsent(region, k -> Lists.newArrayList()).add(casEntry);
            }
            return regionMap;
        } finally {
            stampedLock.unlockRead(stamp);
        }
    }
Returns the list of regions to which the keys belongs.
jraft-rheakv/rheakv-core/src/main/java/com/alipay/sofa/jraft/rhea/client/RegionRouteTable.java