Fix ownership of async tasks

async-message-passing/src/main.rs

@@ -4,7 +4,7 @@ fn main() {
     trpl::run(async {
         let (tx, mut rx) = trpl::channel();
 
-        let tx_fut = async {
+        let tx_fut = async move {
             let vals = vec![
                 String::from("hi"),
                 String::from("from"),
@@ -20,7 +20,7 @@ fn main() {
 
         let rx_fut = async {
             while let Some(value) = rx.recv().await {
-                println!("received '{value}'");
+                eprintln!("received '{value}'");
             }
         };