handle :transaction mode used by SQL.Sandbox #33
   Merged  
   Add this suggestion to a batch that can be applied as a single commit. This suggestion is invalid because no changes were made to the code. Suggestions cannot be applied while the pull request is closed. Suggestions cannot be applied while viewing a subset of changes. Only one suggestion per line can be applied in a batch. Add this suggestion to a batch that can be applied as a single commit. Applying suggestions on deleted lines is not supported. You must change the existing code in this line in order to create a valid suggestion. Outdated suggestions cannot be applied. This suggestion has been applied or marked resolved. Suggestions cannot be applied from pending reviews. Suggestions cannot be applied on multi-line comments. Suggestions cannot be applied while the pull request is queued to merge. Suggestion cannot be applied right now. Please check back later.    
 
The SQL.Sandbox that ecto_sql uses passes along this mode for checkin/checkout. See
lib/ecto/adapters/sql/sandbox.exinecto_sql.Not sure if this is the correct approach though, but it fixed my problem for now.