@Override
    public void toData(DataOutput out,
        SerializationContext context) throws IOException {
      super.toData(out, context);
      out.writeInt(processorId);
      out.writeUTF(regionName);
      DataSerializer.writeObject(key, out);
      DataSerializer.writeObject(aCallbackArgument, out);
      out.writeInt(timeoutMs);
      out.writeInt(ttl);
      out.writeInt(idleTime);

    }
Invoked on the node that has the object
geode-core/src/main/java/org/apache/geode/internal/cache/SearchLoadAndWriteProcessor.java