Based on Ewen's analysis of various Go iterator patterns, using an interface with an interator struct implementation is much slower than an iterator struct implementation without the corresponding iterator interface. That is, just remove PairIterator the interface and promote pairIterator the struct to "PairIterator".
Based on Ewen's analysis of various Go iterator patterns, using an interface with an interator struct implementation is much slower than an iterator struct implementation without the corresponding iterator interface. That is, just remove PairIterator the interface and promote pairIterator the struct to "PairIterator".