Update Ch20

hello/src/lib.rs

@@ -24,7 +24,7 @@ impl ThreadPool {
         let mut workers = Vec::with_capacity(size);
 
         for id in 0..size {
-            workers.push(Worker::new(id));
+            workers.push(Worker::new(id, receiver));
         }
 
         ThreadPool { workers, sender }
@@ -43,8 +43,10 @@ struct Worker {
 }
 
 impl Worker {
-    fn new(id: usize) -> Worker {
-        let thread = thread::spawn(|| {});
+    fn new(id: usize, receiver: mpsc::Receiver<Job>) -> Worker {
+        let thread = thread::spawn(|| {
+            receiver;
+        });
 
         Worker { id, thread }
     }