TransientLifetimeManager could be one instance for all of the policies

[ENikS]

[randylevy]

It could be one instance. Would this affect the public API when explicitly setting a lifetime manager? e.g. Would users still instantiate a new TransientLifetimeManager() to pass in to Register but then that object would not be used internally?

[ENikS]

No, it should not. It only applies to cases where LifetimeManager is null. Once it is allocated and passed in it could be used as is.
.. or we could ignore it and use internal instance.