Impl Send for Timer on Windows

Fixes #20943

Signed-off-by: Peter Atashian <retep998@gmail.com>

src/libstd/io/timer.rs

@@ -227,6 +227,12 @@ mod test {
     use thread::Thread;
     use time::Duration;
 
+    #[test]
+    fn test_timer_send() {
+        let mut timer = Timer::new().unwrap();
+        Thread::spawn(move || timer.sleep(Duration::milliseconds(1)));
+    }
+
     #[test]
     fn test_io_timer_sleep_simple() {
         let mut timer = Timer::new().unwrap();