signal: Ctrl+C example: add explanatory comments

examples/ctrl-c/src/main.rs

@@ -6,12 +6,19 @@ use futures::stream::Stream;
 use tokio_core::reactor::Core;
 
 fn main() {
+    // set up a Tokio event loop
     let mut core = Core::new().unwrap();
+
+    // tokio_signal provides a convenience builder for Ctrl+C
+    // this even works cross-platform, linux and windows!
     let ctrlc = tokio_signal::ctrl_c(&core.handle());
     let stream = core.run(ctrlc).unwrap();
 
     println!("This program is now waiting for you to press Ctrl+C");
 
+    // Up until now, we haven't really DONE anything, just prepared
+    // now it's time to actually schedule, and thus execute, the stream
+    // on our event loop
     core.run(stream.for_each(|()| {
         println!("Ctrl-C received!");
         Ok(())