/*
   * Add a property as key/value pair
   * * Input parameters to 'invoke'd methods are represented as ClientOption properties
   * * Key is evaluated as String
   * * Value is evaluated as String or EndPointReference
   *
   * call-seq:
   *   options.add_property "Key", "Value"
   *   options.add_property "Key", EndPointReference.new(...)
   *
   */
  void add_property(VALUE k, VALUE v)