var session = db.getMongo().startSession();
session.startTransaction({readConcern: { level: ‘majority‘ },writeConcern: { w: ‘majority‘ }});

var coll1 = session.getDatabase(‘students‘).getCollection(‘teams‘);
coll1.update({name: ‘yzw-football-team‘}, {$set: {members: 20}});

var coll2 = session.getDatabase(‘students‘).getCollection(‘records‘);
coll1.update({name: ‘Edison‘}, {$set: {gender: ‘Female‘}});

// 成功提交事务
session.commitTransaction();

// 失败事务回滚
session.abortTransaction();

using (var clientSession = mongoClient.StartSession())
{
    try
    {
        var contacts = clientSession.Client.GetDatabase("testDB").GetCollection<Contact>("contacts");
        contacts.ReplaceOne(contact => contact.Id == "1234455", contact);
        var books = clientSession.Client.GetDatabase("testDB").GetCollection<Book>("books");
        books.DeleteOne(book => book.Id == "1234455");

        clientSession.CommitTransaction();
    }
    catch (Exception ex)
    {
        // to do some logging
        clientSession.AbortTransaction();
    }
}

try (ClientSession clientSession = client.startSession()) {
  clientSession.startTransaction();
  collection.insertOne(clientSession, docOne);
  collection.insertOne(clientSession, docTwo);
  clientSession.commitTransaction();
}