@Override
  public int getDSFID() {
    return HA_EVENT_WRAPPER;
  }
Calls fromData() on ClientUpdateMessage and sets it as its member variable. Also, sets the
referenceCount to zero.

@param in The input stream from which the object should be constructed.
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/HAEventWrapper.java