tokio-reactor: impl AsRawFd for reactor for unix (#890)

In order to support nesting a tokio reactor within another event
system exposing the file descriptor for the underlying reactor
is useful and is already implemented for mio::Poll.

Signed-off-by: Paul Osborne <[email protected]>

tokio-reactor/src/lib.rs

@@ -74,6 +74,8 @@ use std::sync::atomic::Ordering::{Relaxed, SeqCst};
 use std::sync::atomic::AtomicUsize;
 use std::sync::{Arc, Weak};
 use std::time::{Duration, Instant};
+#[cfg(all(unix, not(target_os = "fuchsia")))]
+use std::os::unix::io::{AsRawFd, RawFd};
 
 use log::Level;
 use mio::event::Evented;
@@ -429,6 +431,13 @@ impl Reactor {
     }
 }
 
+#[cfg(all(unix, not(target_os = "fuchsia")))]
+impl AsRawFd for Reactor {
+    fn as_raw_fd(&self) -> RawFd {
+        self.inner.io.as_raw_fd()
+    }
+}
+
 impl Park for Reactor {
     type Unpark = Handle;
     type Error = io::Error;