Inject existing object into MEF2

[gthvidsten]

Say I have an object:

IMyObject obj = SomeFactory.CreateMyObject();
obj.NeedsSomeConfiguration()
    .NeedsMoreConfiguration();

and I've set up MEF to use the current assembly (of which IMyObject is defined)

ContainerConfiguration containerConfig = new ContainerConfiguration()
    .WithAssembly(Assembly.GetExecutingAssembly())

How can I inject the specific instance of obj into this configuration so that I can do the following in an exported class

[Export(typeof(IOtherObject))]
public class OtherObject : IOtherObject
{
    [Import] public IMyObject MyObject { get; set; }
}

[CZEMacLeod]

I'm fairly sure this is partially answered in #29400 by @nblumhardt
The 4 files in Microsoft.Composition.Demos.ExtendedPartTypes give you the ability.
It would be nice if these were bundled up and either included in one of the existing System.Composition.* packages or a new System.Composition.??? package.

Regardless, with the extensions available you can do

ContainerConfiguration containerConfig = new ContainerConfiguration()
    .WithAssembly(Assembly.GetExecutingAssembly())
    .WithExport<IMyObject>(obj);

or even

ContainerConfiguration containerConfig = new ContainerConfiguration()
    .WithAssembly(Assembly.GetExecutingAssembly())
    .WithFactoryDelegate<IMyObject>(() => {
        IMyObject obj = SomeFactory.CreateMyObject();
        obj.NeedsSomeConfiguration()
            .NeedsMoreConfiguration();
        return obj;
    });

or maybe

    .WithFactoryDelegate<IMyObject>(() => SomeFactory.CreateMyObject()
        .NeedsSomeConfiguration()
        .NeedsMoreConfiguration());

[tarekgh]

Closing as dups of #29400 (comment)