Adds example and makes both wav_output functions own source

It does not make sense to get them by ref. Since we will not return
till they are fully exhausted (or never if the source is infinite).
Therefore there is no use to borrowing

Author: dvdsk

src/lib.rs

@@ -199,3 +199,6 @@ pub use crate::stream::{play, OutputStream, OutputStreamBuilder, PlayError, Stre
 #[cfg(feature = "wav_output")]
 #[cfg_attr(docsrs, doc(cfg(feature = "wav_output")))]
 pub use crate::wav_output::output_to_wav;
+#[cfg(feature = "wav_output")]
+#[cfg_attr(docsrs, doc(cfg(feature = "wav_output")))]
+pub use crate::wav_output::collect_to_wav;

src/wav_output.rs

@@ -24,21 +24,37 @@ assert_error_traits!(ToWavError);
 ///
 /// If the file already exists it will be overwritten.
 pub fn output_to_wav(
-    source: &mut impl Source,
+    source: impl Source,
     wav_file: impl AsRef<path::Path>,
 ) -> Result<(), ToWavError> {
-    let file = std::fs::File::create(wav_file)
+    let mut file = std::fs::File::create(wav_file)
         .map_err(Arc::new)
         .map_err(ToWavError::OpenFile)?;
-    collect_to_wav(source, file)
+    collect_to_wav(source, &mut file)
 }
 
 /// Saves Source's output into a writer. The output samples format is 32-bit float. This function
 /// is intended primarily for testing and diagnostics. It can be used to see the output without
 /// opening output stream to a real audio device.
+///
+/// # Example
+/// ```rust
+/// # use rodio::static_buffer::StaticSamplesBuffer;
+/// # use rodio::collect_to_wav;
+/// # const SAMPLES: [rodio::Sample; 5] = [0.0, 1.0, 2.0, 3.0, 4.0];
+/// # let source = StaticSamplesBuffer::new(
+/// #     1.try_into().unwrap(), 
+/// #     1.try_into().unwrap(), 
+/// #     &SAMPLES
+/// # );
+/// let mut writer = std::io::Cursor::new(Vec::new());
+/// collect_to_wav(source, &mut writer)?;
+/// let wav_bytes: Vec<u8> = writer.into_inner();
+/// # Ok::<(), Box<dyn std::error::Error>>(())
+/// ```
 pub fn collect_to_wav(
-    source: &mut impl Source,
-    writer: impl io::Write + io::Seek,
+    source: impl Source,
+    writer: &mut (impl io::Write + io::Seek),
 ) -> Result<(), ToWavError> {
     let format = WavSpec {
         channels: source.channels().get(),