default void postCompletedSplitRegionAction(final ObserverContext<MasterCoprocessorEnvironment> c,
    final RegionInfo regionInfoA, final RegionInfo regionInfoB) throws IOException {
  }
Called after the region is split.
@param c           the environment to interact with the framework and master
@param regionInfoA the left daughter region
@param regionInfoB the right daughter region
hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java