public void updateForWrite(final int modNum) {
    dirty = true;
    modSerialNum = modNum;
  }
Fetches the current modification serial number from the txState and puts it in this entry.

@param modNum the next modified serial number gotten from TXState

@since GemFire 5.0
geode-core/src/main/java/org/apache/geode/internal/cache/TXEntryState.java