Rewriting package to use MongoDB 4.0 Multi-document ACID transactions

[bohan0]

Is there any plans to do this? Been trying to do it this way: https://github.com/meteor/meteor/blob/3051150f2f5ae953f391802e73682fba613b3d46/packages/mongo/mongo_livedata_tests.js#L3431-L3487

but getting a lot of errors like:

UnhandledPromiseRejectionWarning: MongoError: Given transaction number 5 does not match any in-progress transactions.