One critical topic I hope to be discussed in the proposal is Async requirements require duplication of protocols (which is raised in the google doc of another proposal Exploration: Type System Considerations for Actor Proposal). If I have an isolated ownership of an actor, I suppose I can cast it into existentials or do other POP programming. But this proposal doesn't seem to address these issues at the current stage. Do we really need to define almost identical protocols of sync/async versions?