public async Task BsonTest()
{
var clt = _helper.BsonCollection <MTest>();
var projection = Builders <BsonDocument> .Projection.Exclude("_id");
var models = await clt.Find(new BsonDocument()).Project(projection).ToListAsync();
var list = models.ToList();
//var json = JsonConvert.SerializeObject(list);
list.ForEach(Print);
//var updates = new WriteModel<BsonDocument>[]
//{
// new InsertOneModel<BsonDocument>(new BsonDocument("_id", 3)),
// new DeleteOneModel<BsonDocument>(new BsonDocument("_id", 3)),
// new UpdateOneModel<BsonDocument>(new BsonDocument(), new BsonDocument())
//};
//var result = await clt.BulkWriteAsync(updates, new BulkWriteOptions { IsOrdered = true });
//Print(result);
var info = _helper.Database.RunCommand <BsonDocument>(new BsonDocument("buildinfo", 1));
Print(info);
}