To support one-shot transactions, we need to introduce a notion of {autocommit: true} to commit the multi-statement transaction automatically when the command invocation completes. To do that, we will commit instead of stash the transaction when the command with {autocommit: true} succeeds. Technically {autocommit: true} could be attached to any command supported in multi-statement transactions. But we will only allow {autocommit: true} in bulkWrite for now to avoid changes to the semantics of existing commands. Currently, the server assumes that the autocommit field must be false when present (e.g. this and this). So we need to audit the code and make sure consumers of the autocommit field behave correctly when the value is true.