@Override
  public int hashCode() {
    long result = 0;

    if (isSynchronous()) {
      if (isRollOplogs()) {
        result += 2;
      }
    } else {
      result += 1; // asynchronous
      result += getTimeInterval();
      result += getBytesThreshold();
    }
    result += getMaxOplogSize();
    return (int) (result & 0xFFFFFFFF);
  }
Two <code>DiskWriteAttributes</code> are equal if the both specify the synchronous writes, or
they both specify asynchronous writes with the same time interval and bytes threshold.
geode-core/src/main/java/org/apache/geode/internal/cache/DiskWriteAttributesImpl.java