docs: @Nonnull
    public static Enumeration <String> getAllAttributes (@Nonnull final HttpSession aSession)
    {
      ValueEnforcer.notNull (aSession, "Session");
  
      try
      {
        return GenericReflection.uncheckedCast (aSession.getAttributeNames ());
      }
      catch (final IllegalStateException ex)
      {
        // Session no longer valid
        return new EmptyEnumeration <> ();
      }
    }