code: @Nullable
    @OverrideOnDemand
    protected String getLoginName (@Nonnull final IRequestWebScopeWithoutResponse aRequestScope)
    {
      return aRequestScope.params ().getAsString (CLogin.REQUEST_ATTR_USERID);
    }
docs: Get the current login name
  
  @param aRequestScope
  Request scope
  @return <code>null</code> if no login name was present
  @since 3.4.0