Ivan Petkov cbad83f362 signal: migrate to std::futures (#1218)
Migrate to std::futures and the futures 0.3 preview and use async/await
where possible

**Breaking change:** the IoFuture and IoStream definitions used to refer
to Box<dyn Future> and Box<dyn Stream>, but now they are defined as
Pin<...> versions which are technically breaking.

No other breaking or functional changes have been made
2019-07-03 10:40:59 -07:00
..