Add a timer wheel

tests/timeout.rs

@@ -0,0 +1,25 @@
+extern crate env_logger;
+extern crate futures;
+extern crate futures_mio;
+
+use std::time::{Instant, Duration};
+
+use futures::Future;
+
+macro_rules! t {
+    ($e:expr) => (match $e {
+        Ok(e) => e,
+        Err(e) => panic!("{} failed with {:?}", stringify!($e), e),
+    })
+}
+
+#[test]
+fn smoke() {
+    drop(env_logger::init());
+    let mut l = t!(futures_mio::Loop::new());
+    let dur = Duration::from_millis(10);
+    let timeout = l.handle().timeout(dur).and_then(|t| t);
+    let start = Instant::now();
+    t!(l.run(timeout));
+    assert!(start.elapsed() >= dur);
+}