private byte getSizeOfOffset() {
    int size = dis.size();
    if (size <= MAX_UNSIGNED_BYTE) {
      return DataSize.BYTE_SIZE;
    } else if (size <= MAX_UNSIGNED_SHORT) {
      return DataSize.SHORT_SIZE;
    }
    return DataSize.INTEGER_SIZE;
  }
@return size of each variable length field offset
geode-core/src/main/java/org/apache/geode/pdx/internal/PdxReaderImpl.java