ROOTObjectWriter: Re-add TProcessID::SetObjectCount()

void ROOTObjectWriterModule::run(Event* event) {

    auto root_lock = root_process_lock();

    // Retrieve current object count:

    auto object_count = TProcessID::GetObjectCount();

    // Fetch filtered messages

    auto messages = messenger_->fetchFilteredMessages(this, event);

    // Mark objects to be stored:

        // Fill the branch vector

        for(Object& object : object_array) {

            // Trigger the creation of TRefs for cross-object references to be able to store them to file.

            // We can reset the TObject count after processing this event because the TRef creation is only done here locally

            // in one worker thread instead of framew-work wide.

            object.petrifyHistory();

            ++write_cnt_;

            write_list_[index_tuple]->push_back(&object);

    for(auto& index_data : write_list_) {

        index_data.second->clear();

    }

    // We can reset the TObject count after processing this event because the TRef creation is only done here locally

    // in one worker thread instead of framework wide.

    TProcessID::SetObjectCount(object_count);

}

void ROOTObjectWriterModule::finalize() {