Macro erase_streaming_handler_with_state 

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

Erase a streaming handler with state + typed args into an ErasedStreamHandler.

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