Delay never fails

[ntkoopman]

Hi, I'm on a mac and I keep getting the following error. Seems like it does in fact sometimes fails.

thread 'main' panicked at 'delay never fails: Error(Shutdown)', libcore/result.rs:945:5
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
   1: std::sys_common::backtrace::print
   2: std::panicking::default_hook::{{closure}}
   3: std::panicking::default_hook
   4: std::panicking::rust_panic_with_hook
   5: std::panicking::begin_panic_fmt
   6: rust_begin_unwind
   7: core::panicking::panic_fmt
   8: core::result::unwrap_failed
   9: <tk_listen::sleep_on_error::SleepOnError<S> as futures::stream::Stream>::poll
  10: <futures::stream::map::Map<S, F> as futures::stream::Stream>::poll
  11: futures::task_impl::std::set
  12: <std::thread::local::LocalKey<T>>::with
  13: tokio_current_thread::block_on_all
  14: proxy::main
  15: std::rt::lang_start::{{closure}}
  16: std::panicking::try::do_call
  17: __rust_maybe_catch_panic
  18: std::rt::lang_start_internal
  19: main

[tailhook]

Wow! That's interesting. It seems changed since tokio-core times :( I'm not entirely sure that this is a bug though.

I.e. it will probably work if you have an explicit way to shutdown the listener:

let (tx, rx) = oneshot::channel()
spawn(listener.select(rx)); // some type conversions needed

Can you show more code of how do you use block_on_all?

Frankly, I'm not sure how to handle error. The issue is that if we return Err from a stream then listener.buffer_unordered(n) might close prematurely. Returning "end of stream" seems invalid too.

It's also unclear what to do with "at_capacity" errors. Skipping a timer in that case defeats the whole purpose of "preventing DoS" that this timer is for.