const collection = db.collection('test', { raw: true });

// ok: returns buffer
await collection.find({}).limit(1).toArray();
// also ok because it uses find under the hood
await collection.findOne({});

// not ok: returns deserialized document
await collection.aggregate([{ $limit: 1 }]).toArray();
// returns buffer as expected when option is set on operation level
await collection.aggregate([{ $limit: 1 }], { raw: true }).toArray();

// not ok: returns deserialized data
await collection.distinct('_id');
// not ok: returns deserialized document
await collection.insertOne({ x: 1 });
// ...etc