DRIVERS-3411 : Summary of necessary driver changes  This is an addition to DRIVERS-3239 Commits for syncing spec/prose tests (and/or refer to an existing language POC if needed) *  https://github.com/mongodb/specifications/commit/7789704effa04ccde11d7e383c23203e2dd0c509 Context for other referenced/linked tickets  Extended the command assertions in a single test (retry succeeds if backpressure labels are added to the first operation in a transaction) to verify that startTransaction: true is present on both insert (the initial attempt and retry).