Function gstreamer_audio_sys::gst_audio_channel_mixer_new_with_matrix

pub unsafe extern "C" fn gst_audio_channel_mixer_new_with_matrix(
    flags: GstAudioChannelMixerFlags, 
    format: GstAudioFormat, 
    in_channels: c_int, 
    out_channels: c_int, 
    matrix: *mut *mut c_float
) -> *mut GstAudioChannelMixer

This is supported on crate feature v1_14 only.