I tried the TileLayer in the 4.x on a non-cached service and get an error (Cannot read property 'pause' of null. from MapView.js.
What I am after is the API to split (tile) the request into smaller requests and return images as they are rendered by ArcGIS Server.
There is nothing like that in the 4.x API. You have TileLayer which is for cached services and MapImageLayer which is for non-cached dynamic services.