@Override
  public void toData(DataOutput out) throws IOException {
    if (session != null) {
      value = session.getAttribute(name);
      blobifyValue();
    }
    out.writeBoolean(update);
    DataSerializer.writeString(name, out);
    DataSerializer.writeObject(value, out);
  }
Constructor which creates a 'deferred' event. This is used when the value should only be
applied when the object is serialized.

@param session the session from which the value ultimately will be retrieved
@param attribute the name of the attribute
extensions/geode-modules-session-internal/src/main/java/org/apache/geode/modules/session/internal/filter/attributes/DeltaEvent.java