You can have a DO proxy each user connection, then they forward messages to the multipler document. The user proxy deals with ordering and buffering their connection message state in the presence of disconnects, and the document DO handles the shared state.
It's actors plus a global routing system that means all messages addressed to a unique identifier will arrive in the actor instance. I haven't seen any other actor frameworks that provide that.
You can have a DO proxy each user connection, then they forward messages to the multipler document. The user proxy deals with ordering and buffering their connection message state in the presence of disconnects, and the document DO handles the shared state.