Macro erase_streaming_handler_with_state_only 

macro_rules! erase_streaming_handler_with_state_only {
    ($handler:expr, $state_ty:ty, $states:expr) => { ... };
}

Erase a streaming handler with state only into an ErasedStreamHandler.

The handler must be an async fn(State<Arc<S>>, StreamSender) -> R.