Since snapshot readConcern is supported within txns, Need to update operations that support txns.

Scope of work (see below as a curated list from the readConcern snapshot ticket)

• find
• getMore
  • Note that it will not actually be possible to specify the readConcern level "snapshot" for getMore. Instead, it will inherit its readConcern from the originating command, as it does today.
• parallelCollectionScan Not allowed in txns
• aggregate (including $lookup and $geoNear)
  • but not $out. The $out stage will be prohibited for use within pipelines executed with readConcern level snapshot due to use of metadata operations.
• distinct
• group Since not allowed within transactions
• geoNear (deprecated) Since not allowed in transactions
• geoSearch
• insert
• update (single & multi)
• delete (single & multi)
• findAndModify

Reviewers

Culled from the various server tickets

• Tess
• David
• James
• Siyuan