Solutions for dedicated authoritative server for real-time multiplayer game

I'm looking for solutions that work with Unity for dedicated, authoritative servers for real-time, multiplayer games.

Requirements:

1. Ability to write server code

2. Game rooms

3. Load balancing

Something like Heroku, but for real-time multiplayer game servers, would be perfect. Options I've consider:

PUN - doesn't allow server code. UNET - player hosts (not dedicated server) Heroku - only allows HTTP connections (not good for real-time games)

Anyone have any suggestions?