Don't use channels to send dependencies

src/builder.rs

@@ -65,7 +65,7 @@ impl IsUnitType for () {}
 /// let b = b.depends_on(&a);
 /// // Now b is a TaskHandle<i32>
 ///
-/// dag.run(|fut| { tokio::spawn(fut); }).await.unwrap();
+/// dag.run().await.unwrap();
 /// assert_eq!(dag.get(&b).unwrap(), 20);
 /// # };
 /// ```
@@ -125,7 +125,7 @@ impl<'a, Tk: Task, Deps> TaskBuilder<'a, Tk, Deps> {
     /// // Multiple dependencies: tuple form
     /// let sum = dag.add_task(Add).depends_on((&x, &y));
     ///
-    /// dag.run(|fut| { tokio::spawn(fut); }).await.unwrap();
+    /// dag.run().await.unwrap();
     /// # };
     /// ```
     pub fn depends_on<D>(self, deps: D) -> TaskHandle<Tk::Output>