pub fn init_maybeuninit_io_slices_mut<'a, 'io_slice, Iterable>(
    uninit_io_slices: &'a mut [MaybeUninit<IoSlice<'io_slice>>],
    iterable: Iterable
) -> &'a mut [IoSlice<'io_slice>]where
    Iterable: IntoIterator<Item = IoSlice<'io_slice>>,