Improve instructions, fix a function call that had been renamed in one place but not others

exercise/threads_channels/src/main.rs

@@ -46,7 +46,7 @@ fn main() {
     // - Create variables `tx` and `rx` and assign them to the sending and receiving ends of an
     // unbounded channel. Hint: An unbounded channel can be created with `channel::unbounded()`
 
-/*
+    /*
         // let ...
 
         // Cloning a channel makes another variable connected to that end of the channel so that you can
@@ -55,24 +55,26 @@ fn main() {
 
         // 4. Examine the flow of execution of "Thread A" and "Thread B" below. Do you see how their
         // output will mix with each other?
-    // - Increase the value passed to the first `pause_ms()` call in "Thread A" so that both the
-    // "Thread B" outputs occur before the "Thread A" outputs.
+        // - Run this code. Notice the order of output from Thread A and Thread B.
+        // - Increase the value passed to the first `sleep_ms()` call in Thread A so that both the
+        // Thread B outputs occur *before* Thread A outputs anything.
+        // - Run the code again and make sure the output comes in a different order.
 
         // Thread A
         let handle_a = thread::spawn(move || {
-        pause_ms(0);
+            sleep_ms(0);
             tx2.send("Thread A: 1").unwrap();
-        pause_ms(200);
+            sleep_ms(200);
             tx2.send("Thread A: 2").unwrap();
         });
 
-    pause_ms(100); // Make sure Thread A has time to get going before we spawn Thread B
+        sleep_ms(100); // Make sure Thread A has time to get going before we spawn Thread B
 
         // Thread B
         let handle_b = thread::spawn(move || {
-        pause_ms(0);
+            sleep_ms(0);
             tx.send("Thread B: 1").unwrap();
-        pause_ms(200);
+            sleep_ms(200);
             tx.send("Thread B: 2").unwrap();
         });
 
@@ -86,7 +88,7 @@ fn main() {
 
         // 5. Oops, we forgot to join "Thread A" and "Thread B". That's bad hygiene!
         // - Use the thread handles to join both threads without getting any compiler warnings.
-*/
+    */
 
     // Challenge: Make two child threads and give them each a receiving end to a channel.  From the
     // main thread loop through several values and print each out and then send it to the channel.