Roman Artiukhin

Please don't review while it's WIP. It's in working state AFAIK but not polished and no dedicated tests

> but maybe there is a workaround You can try to force session to open async connection before calling `session.BeginTransaction`. Something like: ```C# await (session.GetSessionImplementation().ConnectionManager.GetConnectionAsync(cancelationToken)).ConfigureAwait(false); ```

> The running application has just one session factory, but in the configuration we set-up a custom IConnectionProvider. Are you aware there is `IMultiTenancyConnectionProvider` for your needs since NHibernate 5.3?...

> We have a non-trivial set of services required in order to determine "which tenant is active" and to then get that connection string. Well you don't really need to...

> What should we do? We can store proxy in cache.

> I checked my code: the factory is not disposed, the session is not disposed also. How did you check it? Did you check `factory.IsClosed` when exception occurred?

> what is the conclusion on this PR? It's not ready. I removed it from 5.4 milestone

> DB2 requires similar to Firebird workaround I don't really like how it's done in Firebird. We need to think about more elegant solution rather than "brute force" parameters wrapping...

```C# 171) Error : NHibernate.Test.TypesTest.StringTypeWithLengthFixture.HqlEqualityParameterCanExceedColumnSize NHibernate.Exceptions.GenericADOException : could not execute query [ select stringclas0_.Id as id1_0_, stringclas0_.StringValue as stringvalue2_0_, stringclas0_.LongStringValue as longstringvalue3_0_ from StringClass stringclas0_ where stringclas0_.StringValue=@p0 ] Name:likeValue -...

> I was thinking about this. But why? Just to check how it works... It's the latest version. So why not?