Cancel a call invitation

Before an invitation is accepted, the inviter can call signalingCancel():

OpenIMClient.getInstance().signalingManager.signalingCancel(
    new OnBase<String>() {
        @Override
        public void onSuccess(String result) {
            // The signaling request completed.
        }

        @Override
        public void onError(int code, String error) {
            // code and error describe the failure.
        }
    },
    activeInfo
);

Pass the complete SignalingInfo saved when the call was started, not a new object containing only roomID. A successful callback means that the cancel signaling request completed; the application should also end the local pending-answer state and release unused media resources. Remote clients update through onInvitationCancelled.