Method shouldDoUpdate

src/QLContext.actor.cpp:251–261

	                                   DataKey documentPath) = 0;

	Reference<DocumentDeferred> shouldDoUpdate(Reference<DocTransaction> tr, DataKey const& documentKey) {
		ASSERT(documentKey.startsWith(collectionPath) && documentKey.size() > collectionPath.size());
		std::string documentPrefix = documentKey.toString();
		auto deferredDocument = tr->deferredDocuments.find(documentPrefix);
		if (deferredDocument == tr->deferredDocuments.end())
			deferredDocument =
			    tr->deferredDocuments
			        .insert(std::make_pair(documentPrefix, Reference<DocumentDeferred>(new DocumentDeferred())))
			        .first;
		return (*deferredDocument).second;
	}

	void set(Reference<DocTransaction> tr, DataKey key, ValueRef value) override {
		DataKey documentPrefix = key.keyPrefix(collectionPath.size() + 1);