@Override
        public void deleteRange(final ColumnFamilyHandle columnFamily, final byte[] from, final byte[] to) throws RocksDBException {
            db.deleteRange(columnFamily, wOptions, from, to);
        }
Return an approximate count of key-value mappings in this store.

<code>RocksDB</code> cannot return an exact entry count without doing a
full scan, so this method relies on the <code>rocksdb.estimate-num-keys</code>
property to get an approximate count. The returned size also includes
a count of dirty keys in the store's in-memory cache, which may lead to some
double-counting of entries and inflate the estimate.

@return an approximate count of key-value mappings in the store.
streams/src/main/java/org/apache/kafka/streams/state/internals/RocksDBStore.java