docs: private int computeSimpleCredsHashCode( SimpleCredentials c ) {
          String userID = c.getUserID();
          char[] password = c.getPassword();
          Map<String, Object> m = getAttributeMap(c);
          final int prime = 31;
          int result = 1;
          result = prime * result + ((userID == null) ? 0 : userID.hashCode());
          for (int i = 0; i < password.length; i++) {
              result = prime * result + password[i];
          }
          result = prime * result + ((m == null) ? 0 : m.hashCode());
          return result;
      }