code: public static LocalCall<String> mkdir(String path, String user, String group) {
          return mkdir(path, Optional.of(user), Optional.of(group), Optional.empty());
      }
docs: Ensures that a directory is available
  
  @param path  Path to directory
  @param user  Owner user
  @param group Owner group
  @return      The {@link LocalCall} object to make the call