private static void fastPathWrite(OutputStream out, byte[] register) throws IOException {
    for (byte b : register) {
      out.write(b);
    }
  }
This function deserializes the serialized hyperloglogs from a byte array.
@param buf - to deserialize
@return HyperLogLog
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/common/ndv/hll/HyperLogLogUtils.java