I request for transaction support

[PetroGromovo]

I want to use transactions with jenssegers/mongodb. I tried and failed it.

Searching for a possible decision I found this PR:
#2381

I suppose it could be a decision for my issue...
Could you please check and merge it with latest version of jenssegers/mongodb ?

Thanks in advance!

[agpopov]

I need transactions too...