code: public static List<String> list(URI metadataService, String path) {
      checkArgument(checkNotNull(path, "path").endsWith("/"), "path must end with '/'; %s provided",
                    path);
      String content = get(metadataService, path);
      if (content != null) {
        return split('\n', content);
      }
      return Collections.<String>emptyList();
    }
docs: Retrieves a list of resources at a path, if present.
  
  @param metadataService endpoint with trailing slash. ex. {@code http://169.254.169.254/latest/meta-data/}
  @param path            path of a listable resource, such as {@code iam/security-credentials/};
  must end in slash
  @return empty if {@code metadataService} service cannot be contacted or no data at path.