Function event_loop_stream_option 

pub fn event_loop_stream_option<T: 'static>(
    stream: impl Stream<Item = T> + 'static,
    write: WriteSignal<Option<T>>,
    write_finished: WriteSignal<bool>,
    trigger: ExtSendTrigger,
)

Execute a stream on the main event loop by polling, for Option signals. The stream does not need to be Send.