anchor.diff:          }
         }
       } catch (e) {}
  -
   
   // todo
   // retest1
  
positive.code:   //
    // In test III, the client sends
    // a Binding Request with only the "change port" flag set.
    Future test003({StunRfcVersion version:StunRfcVersion.ref3489}) async {
      StunHeader header = new StunHeader(StunHeader.bindingRequest, version:version);
      header.attributes.add(new StunChangeRequestAttribute(false, true));
      return await sendHeader(header);
    }
  
negative.code:   // In test II, the client sends a
    // Binding Request with both the "change IP" and "change port" flags
    // from the CHANGE-REQUEST attribute set.
    Future<StunClientSendHeaderResult> test002({StunRfcVersion version: StunRfcVersion.ref3489}) async {
      StunHeader header = new StunHeader(StunHeader.bindingRequest, version: version);
      header.attributes.add(new StunChangeRequestAttribute(true, true));
      return await sendHeader(header);
    }
  