Exception User Unhandled once left join is exectuted

[locampoArkus]

Exception User Unhandled
System.Reflection.TargetInvocationException: 'Exception has been thrown by the target of an invocation.'
NotSupportedException: $project or $group does not support {document}.

Same query was runned using MongoDB Driver tool and works perfectly, but using mongoframework thrown this exception.

[Turnerj]

I'm going to guess it is likely due to this line:

MongoFramework/src/MongoFramework/MongoDbConnection.cs

Line 29 in 840ebf0

settings.LinqProvider = MongoDB.Driver.Linq.LinqProvider.V2;

Basically within the MongoDB Driver, they have multiple implementations of the LINQ-backed system. V3 is the default as of 2.14 or something and improves various types of queries. Unfortunately V3 also breaks a bunch of internal hooks that MongoFramework uses and I haven't yet had the time to fix all the issues.

I thought I had a draft PR up of my progress for it but I guess I never pushed it - will have to dig that up at some point.