Distributed lock with added expiry.

DistributedLock.cs

 var response = await collection.FindOneAndUpdateAsync<LockModel>(
  // Find a record with the lock ID
  x => x.Id == lockId,
  // If our 'upsert' creates a document, set the ID to the lock ID
  Builders<LockModel>.Update
    .SetOnInsert(x => x.Id, lockId)
    .SetOnInsert(x => x.ExpireAt, DateTime.UtcNow.AddMinutes(1)),
  new FindOneAndUpdateOptions<LockModel>
  {
    // If the record doesn't exist, create it.
    IsUpsert = true,
    // Specifies that the result we want is the record BEFORE it
    // was created (this is important).
    ReturnDocument = ReturnDocument.Before
  });