Feature: User defined mapping

It would be nice, if you could define your own mapping for the async-to-sync function conversion.

Example:

NHibernate.Linq.LinqExtensionMethods.ToListAsync=System.Linq.Enumerable.ToList

Currently, this source code generator tries to use NHibernate.Linq.LinqExtensionMethods.ToList, which doesn't exist and requires to write your own class, like:

namespace NHibernate.Linq;

internal static class LinqExtensionMethods
{
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static List<T> ToList<T>(IQueryable<T> query)
        => query.ToList();
}

This, however, comes with its own problems:

• Complaints that the namespace doesn't match the directory structure/root namespace of the project
• Warning CS0436, because there is a static class in both the NHibernate assembly and your own project

The mapping could be stored in a file included with AdditionalFiles, like the CsWin32 project does.

Start by locating the source code generator entry point that performs async-to-sync method conversion and reviewing how AdditionalFiles are exposed. Define how the mapping file represents entries such as the ToListAsync example, then verify that configured mappings are used instead of generated wrapper methods without requiring user-defined classes.