Remove examples/busy_loop.rs, update examples/app.rs

Author: Jeff Lai

console-subscriber/examples/app.rs

@@ -11,6 +11,7 @@ OPTIONS:
     blocks      Includes a (misbehaving) blocking task
     burn        Includes a (misbehaving) task that spins CPU with self-wakes
     coma        Includes a (misbehaving) task that forgets to register a waker
+    noyield      Includes a (misbehaving) task that spawns tasks that never yield
 "#;
 
 #[tokio::main]
@@ -38,6 +39,12 @@ async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
                     .spawn(burn(1, 10))
                     .unwrap();
             }
+            "noyield" => {
+                tokio::task::Builder::new()
+                    .name("noyield")
+                    .spawn(no_yield(20))
+                    .unwrap();
+            }
             "help" | "-h" => {
                 eprintln!("{}", HELP);
                 return Ok(());
@@ -114,3 +121,17 @@ async fn burn(min: u64, max: u64) {
         }
     }
 }
+
+#[tracing::instrument]
+async fn no_yield(seconds: u64) {
+    loop {
+        let handle = tokio::task::Builder::new()
+            .name("greedy")
+            .spawn(async move {
+                std::thread::sleep(Duration::from_secs(seconds));
+            })
+            .expect("Couldn't spawn greedy task");
+
+        _ = handle.await;
+    }
+}