docs: static long getHiFieldOffset(final Format format, final HiField hiField) {
      final int formatIdx = format.ordinal();
      final int hiFieldIdx = hiField.ordinal();
      final long fieldOffset = hiFieldOffset[formatIdx][hiFieldIdx] & 0xFF; //initially a byte
      if (fieldOffset == 0) {
        throw new SketchesStateException("Undefined preamble field given the Format: "
            + "Format: " + format.toString() + ", HiField: " + hiField.toString());
      }
      return fieldOffset;
    }