default List<String> contributors(String owner) {
      return repos(owner).stream()
          .flatMap(repo -> contributors(owner, repo.name).stream())
          .map(c -> c.login)
          .distinct()
          .collect(Collectors.toList());
    }
Lists all contributors for all repos owned by a user.
example-github/src/main/java/example/github/GitHubExample.java