play cant be async oddly enough because device goes out of scope and kills thread

src/main.rs

@@ -12,25 +12,26 @@ fn main() {
         flags.sound_font,
         flags.sample_rate,
     );
-
-    let params = OutputDeviceParameters {
-        channels_count: 2,
-        sample_rate: flags.sample_rate,
-        channel_sample_count: flags.sample_rate / flags.bpm * 60 / flags.smallest_note, 
-    };
-
     // Play some notes (middle C, E, G). // 16 channels actually // 60=c 64=e 67=g //up to 128velocity though dont go below 50 tbh // 12 notes per octave
     syn.note_on(0, 64 + 12, 127);
-    //syn.render(&mut left[..], &mut right[..]); // puts in a state of rendering the first loop of these notes
 
-    // The recycled output buffer per-loop, could be in lamba but that'd be wasteful
+    play(syn, flags.sample_rate, flags.bpm, flags.smallest_note);
+}
+
+fn play(mut s: syn::Syn, sample_rate: usize, bpm: usize, smallest_note: usize) {
+    let params = OutputDeviceParameters {
+        channels_count: 2,
+        sample_rate: sample_rate,
+        channel_sample_count: sample_rate / bpm * 60 / smallest_note, 
+    };
+
     let sample_count = (params.channel_sample_count) as usize;
     let mut left: Vec<f32> = vec![0_f32; sample_count];
     let mut right: Vec<f32> = vec![0_f32; sample_count];
-    // Start the audio output. Executes channel_sample_count per loop, sample_rate/channel_sample_count per second forever.
+
     let _device = run_output_device(params, {
         move |data| {
-            syn.render(&mut left[..], &mut right[..]); // put in a state of rendering the next loop of these notes
+            s.render(&mut left[..], &mut right[..]); // put in a state of rendering the next loop of these notes
             for (i, value) in left.iter().interleave(right.iter()).enumerate() {
                 data[i] = *value;
             }
@@ -38,7 +39,6 @@ fn main() {
     })
     .unwrap();
 
-    // Let it ride
+    // Wait it out
     std::thread::sleep(std::time::Duration::from_secs(2));
 }
-