fix multi example

examples/multi.rs

@@ -11,14 +11,19 @@ fn main() {
     .unwrap()
     .progress_chars("##-");
 
+    let mut pb_set = vec![];
+
     let pb = m.add(ProgressBar::new(128));
     pb.set_style(sty.clone());
+    pb_set.push(pb.clone());
 
     let pb2 = m.insert_after(&pb, ProgressBar::new(128));
     pb2.set_style(sty.clone());
+    pb_set.push(pb2.clone());
 
     let pb3 = m.insert_after(&pb2, ProgressBar::new(1024));
     pb3.set_style(sty);
+    pb_set.push(pb3.clone());
 
     m.println("starting!").unwrap();
 
@@ -60,5 +65,8 @@ fn main() {
 
     let _ = h1.join();
     let _ = h2.join();
-    m.clear().unwrap();
+
+    for pb in pb_set.drain(..) {
+        pb.finish_and_clear();
+    }
 }