private static Boolean isAligned(byte flag) {
    if ((flag & 0x04) != 0) {
      return null;
    } else {
      return (flag & 0x02) == 2;
    }
  }
Including schema and pre-delete flag of a measurement, could be expanded further.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/pbtree/schemafile/RecordUtils.java