cancel method
Calling this method tells MobileFirst Platform that the challenge that you no longer want to take any actions to attempt to resolve the challenge. This method returns control to MobileFirst Platform for further handling. For example, call this method when the user clicks on a cancel button.
Implementation
cancel() {
_channel.invokeMethod(WLCLIENT_CANCEL_CHALLENGE,
<String, dynamic>{SECURITY_CHECKNAME: securityCheck});
}