the associated iterators of `SmallVec` are: - `Drain` => `drain.rs` - `IntoIter` => `intoiter.rs` - `Splice` => `splice.rs` - `ExtractIf` => `extractif.rs` each of those iterators should be moved into their file with all its methods and implementations
the associated iterators of
SmallVecare:Drain=>drain.rsIntoIter=>intoiter.rsSplice=>splice.rsExtractIf=>extractif.rseach of those iterators should be moved into their file with all its methods and implementations