Function PSPropertyBag_ReadUnknown 

pub unsafe fn PSPropertyBag_ReadUnknown<P0, P1>(
    propbag: P0,
    propname: P1,
    riid: *const GUID,
    ppv: *mut *mut c_void,
) -> Result<()>
where
    P0: Param<IPropertyBag>,
    P1: Param<PCWSTR>,