/** 
* Aggregation Callback 
*/
void
aggregateCallback(LogEntryHandle handle, uint8_t type,
                      void *cookie)
{
        const Object* obj = handle->userData<Object>();
        MasterServer *server = reinterpret_cast<MasterServer*>(cookie);

        int *p;
        p = (int*) obj->data;
        server->sum += (uint64_t)*p;       
}