impl IEnumUnknown {
    pub unsafe fn Next(&self, rgelt: &mut [Option<windows_core::IUnknown>], pceltfetched: Option<*mut u32>) -> windows_core::HRESULT
    // ...
}

pub trait IEnumUnknown_Impl: windows_core::IUnknownImpl {
    fn Next(&self, celt: u32, rgelt: windows_core::OutRef<'_, windows_core::IUnknown>, pceltfetched: *mut u32) -> windows_core::HRESULT;
    // ...
}

impl<T: Type<T>> OutRef<'_, T> {
    // ...
    pub fn write(self, value: T::Default) -> Result<()> {
        if self.0.is_null() {
            Err(Error::from_hresult(imp::E_POINTER))
        } else {
            unsafe { *self.0 = core::mem::transmute_copy(&value) }
            core::mem::forget(value);
            Ok(())
        }
    }
}