#includeIn this example, we use the basic BSON document builder to create a document with a key "date" and a value equal to the current system time in the form of a BSON date. The BSONObjBuilder::appendDate method is part of the mongocxx package library, which is a C++11 driver for MongoDB used to interact with MongoDB databases.#include using namespace std::chrono; using bsoncxx::builder::basic::make_document; using bsoncxx::builder::basic::kvp; using bsoncxx::builder::basic::types::b_date; auto now = system_clock::now(); bsoncxx::document::value doc_value = make_document(kvp("date", b_date{now}));