我认为没有必要再为生存期管理器设置Context策略，我们只需要在RegisterEventArgs上设置生存期管理器，沿着所示：

public class DefaultLifetimeManagerExtension : UnityContainerExtension
{
    private readonly LifetimeManager _lifetimeManager;

    public DefaultLifetimeManagerExtension(LifetimeManager lifetimeManager)
    {
        _lifetimeManager = lifetimeManager;
    }

    protected override void Initialize()
    {
        // Set the default lifetime manager for registrations
        Context.Registering += (sender, e) =>
        {
            if (e.LifetimeManager == null)
            {
                e.LifetimeManager = _lifetimeManager;
            }
        };
    }
}