use std::{future, pin::Pin}; use futures::{stream, Stream}; use juniper::graphql_subscription; type BoxStream<'a, I> = Pin + Send + 'a>>; struct ObjA; #[graphql_subscription] impl ObjA { fn id(&self) -> BoxStream<'static, bool> { Box::pin(stream::once(future::ready(true))) } } fn main() {}