@Override
  protected boolean shouldFlush(HStore store) {
    return super.shouldFlush(store) || region.shouldFlushStore(store);
  }
A {@link FlushPolicy} that only flushes store larger a given threshold. If no store is large
enough, then all stores will be flushed.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/FlushAllLargeStoresPolicy.java