+str #15904 Ported Tcp IO to new Stream DSL

* Port of Tcp IO to the new Stream DSL
* ~~Ordered shutdown of the server is to be discussed (was missing in the old one as well)~~
* ~~This PR also includes the broadcast fixes for #15948 which can be ignored (will be removed)~~

Fixes #15904
I thought that we decide to go with this style for now. It can of course be revised, but I feel that you need to be able to signal some back pressure on how many connections you are accepting. Does it need to go in before tomorrow?