Write specs for Enumerator::Lazy#zip
Implement Enumerator::Lazy#zip
Write specs for Enumerator::Lazy#{to_enum,enum_for}
Implement Enumerator::Lazy#{to_enum,enum_for}
Refactor Enumerator::Lazy#{initialize,to_enum,enum_for}
Avoid &block in {Enumerable::}Enumerator#each

https://github.com/rubinius/rubinius/pull/2529\#issuecomment-22382172