pub unsafe extern "C" fn gst_device_provider_factory_get_metadata(
factory: *mut GstDeviceProviderFactory,
key: *const c_char,
) -> *const c_char
pub unsafe extern "C" fn gst_device_provider_factory_get_metadata(
factory: *mut GstDeviceProviderFactory,
key: *const c_char,
) -> *const c_char