code: public void processSubscribe(long timeout, int statusCode, String reasonPhrase,
        int overrideDuration, EventHeader overrideEvent) {
      setErrorMessage("");
  
      PhoneB b = new PhoneB(timeout + 500, statusCode, reasonPhrase, overrideDuration, overrideEvent);
      b.start();
    }
docs: Same as the other processSubscribe() except allows for a couple of overrides for testing error
  handling by the far end outbound SUBSCRIBE side: (a) this method takes a duration for
  overriding what would normally/correctly be sent back in the response (which is the same as
  what was received in the SUBSCRIBE request or default 3600 if none was received). Observed if
  &gt;= 0. (b) this method takes an EventHeader for overriding what would normally/correctly be
  sent back in the respone (same as what was received in the request).