Try fix the OSX code with futures

src/coreaudio/mod.rs

@@ -10,7 +10,10 @@ use SamplesRate;
 use ChannelPosition;
 use UnknownTypeBuffer;
 
-use futures::{Poll, Task, TaskHandle};
+use futures::Poll;
+use futures::Async;
+use futures::task::Task;
+use futures::task;
 use futures::stream::Stream;
 use std::sync::{Arc, Mutex};
 
@@ -94,7 +97,7 @@ pub struct SamplesStream {
 
 
 struct SamplesStreamInner {
-    scheduled_task: Option<TaskHandle>,
+    scheduled_task: Option<Task>,
     current_callback: Option<render_callback::Args<data::NonInterleaved<f32>>>,
 }
 
@@ -102,7 +105,7 @@ impl Stream for SamplesStream {
     type Item = UnknownTypeBuffer;
     type Error = ();
 
-    fn poll(&mut self, _: &mut Task) -> Poll<Option<Self::Item>, Self::Error> {
+    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
         let mut inner = self.inner.lock().unwrap();
 
         // There are two possibilites: either we're answering a callback of coreaudio and we return
@@ -110,7 +113,10 @@ impl Stream for SamplesStream {
 
         let current_callback = match inner.current_callback.take() {
             Some(c) => c,
-            None => return Poll::NotReady
+            None => {
+                self.inner.lock().unwrap().scheduled_task = Some(task::park());
+                return Ok(Async::NotReady);
+            }
         };
 
         let buffer_len = current_callback.num_frames * current_callback.data.channels().count();
@@ -120,11 +126,7 @@ impl Stream for SamplesStream {
             buffer: vec![0.0; buffer_len],
         };
 
-        Poll::Ok(Some(UnknownTypeBuffer::F32(::Buffer { target: Some(buffer) })))
-    }
-
-    fn schedule(&mut self, task: &mut Task) {
-        self.inner.lock().unwrap().scheduled_task = Some(task.handle().clone());
+        Ok(Async::Ready(Some(UnknownTypeBuffer::F32(::Buffer { target: Some(buffer) }))))
     }
 }
 
@@ -171,9 +173,9 @@ impl Voice {
 
                 // It is important that `inner` is unlocked here.
                 if let Some(scheduled) = scheduled {
-                    // Calling `notify()` should immediately call `poll()` on the `SamplesStream`,
+                    // Calling `unpark()` should eventually call `poll()` on the `SamplesStream`,
                     // which will use the data we stored in `current_callback`.
-                    scheduled.notify();
+                    scheduled.unpark();
                 }
 
                 // TODO: what should happen if the callback wasn't processed? in other word, what