Add a few comments to clarify examples

Author: HEnquist

examples/feedback_interleaved.rs

@@ -98,6 +98,10 @@ fn main() -> Result<(), coreaudio::Error> {
         let Args {
             num_frames, data, ..
         } = args;
+        // Print the number of frames the callback requests.
+        // Included to aid understanding, don't use println and other things 
+        // that may block for an unknown amount of time inside the callback
+        // of a real application.
         println!("input cb {} frames", num_frames);
         let buffer_left = producer_left.lock().unwrap();
         let buffer_right = producer_right.lock().unwrap();
@@ -116,6 +120,7 @@ fn main() -> Result<(), coreaudio::Error> {
         let Args {
             num_frames, data, ..
         } = args;
+        // Print the number of frames the callback requests.
         println!("output cb {} frames", num_frames);
         let buffer_left = consumer_left.lock().unwrap();
         let buffer_right = consumer_right.lock().unwrap();

examples/sine.rs

@@ -41,6 +41,9 @@ fn main() -> Result<(), coreaudio::Error> {
     // Construct an Output audio unit that delivers audio to the default output device.
     let mut audio_unit = AudioUnit::new(IOType::DefaultOutput)?;
 
+    // Read the input format. This is counterintuitive, but it's the format used when sending
+    // audio data to the AudioUnit representing the output device. This is separate from the
+    // format the AudioUnit later uses to send the data to the hardware device.
     let stream_format = audio_unit.input_stream_format()?;
     println!("{:#?}", &stream_format);
 

examples/sine_advanced.rs

@@ -136,6 +136,10 @@ fn main() -> Result<(), coreaudio::Error> {
             let Args {
                 num_frames, data, ..
             } = args;
+            // Print the number of frames the callback requests.
+            // Included to aid understanding, don't use println and other things 
+            // that may block for an unknown amount of time inside the callback
+            // of a real application.
             println!("frames: {}", num_frames);
             for i in 0..num_frames {
                 let sample_l = samples_l.next().unwrap();