pub trait SetupProxyInterface: Send + Sync {
type GetViewRefsResponseFut: Future<Output = Result<(ViewRef, ViewRef), Error>> + Send;
type WatchViewportResponseFut: Future<Output = Result<Viewport, Error>> + Send;
// Required methods
fn get_view_refs(&self) -> Self::GetViewRefsResponseFut;
fn watch_viewport(&self) -> Self::WatchViewportResponseFut;
}