Map<byte[], AtomicInteger> getPreparePutToStoreMap() {
    return preparePutToStoreMap;
  }
{@link #init(Configuration)} is called for every Store that opens on a RegionServer. Here we
make a lightweight attempt to log this message once per RegionServer, rather than per-Store.
The goal is just to draw attention to this feature if debugging overload due to heavy writes.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/throttle/StoreHotnessProtector.java