pub unsafe fn MFBeginCreateFile<P0, P1, P2>(
    accessmode: MF_FILE_ACCESSMODE,
    openmode: MF_FILE_OPENMODE,
    fflags: MF_FILE_FLAGS,
    pwszfilepath: P0,
    pcallback: P1,
    pstate: P2
) -> Result<IUnknown>
where P0: IntoParam<PCWSTR>, P1: IntoParam<IMFAsyncCallback>, P2: IntoParam<IUnknown>,