1808     type Item = I::Item;  typedef
1809     fn next(&mut self) -> Option<I::Item> {  in next()
1815     fn nth(&mut self, n: usize) -> Option<I::Item> {  in nth()
1818     fn last(self) -> Option<I::Item> {  in last()
1824     type Item;  typedef
1825     fn last(self) -> Option<Self::Item>;  in last()
1829     type Item = I::Item;  typedef
1830     default fn last(self) -> Option<I::Item> {  in last()
1844     fn last(self) -> Option<I::Item> {  in last()
1851     fn next_back(&mut self) -> Option<I::Item> {  in next_back()
1854     fn nth_back(&mut self, n: usize) -> Option<I::Item> {  in nth_back()
1903     fn from_iter<T: IntoIterator<Item = I>>(iter: T) -> Self {  in from_iter()
2019     type Item = S::Item;  typedef
2021     fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {  in poll_next()