in cubeb-core/src/stream.rs [348:353]
fn stream_params_raw_prefs() {
let mut raw: super::ffi::cubeb_stream_params = unsafe { mem::zeroed() };
raw.prefs = super::ffi::CUBEB_STREAM_PREF_LOOPBACK;
let params = unsafe { StreamParamsRef::from_ptr(&mut raw) };
assert_eq!(params.prefs(), StreamPrefs::LOOPBACK);
}