Amazon.IdentityManagement.AmazonIdentityManagementServiceClient.AddUserToGroupAsync C# (CSharp) Method

        public void AddUserToGroupAsync(AddUserToGroupRequest request, AmazonServiceCallback<AddUserToGroupRequest, AddUserToGroupResponse> callback, AsyncOptions options = null)
        {
            options = options == null?new AsyncOptions():options;
            var marshaller = new AddUserToGroupRequestMarshaller();
            var unmarshaller = AddUserToGroupResponseUnmarshaller.Instance;
            Action<AmazonWebServiceRequest, AmazonWebServiceResponse, Exception, AsyncOptions> callbackHelper = null;
            if(callback !=null )
                callbackHelper = (AmazonWebServiceRequest req, AmazonWebServiceResponse res, Exception ex, AsyncOptions ao) => { 
                    AmazonServiceResult<AddUserToGroupRequest,AddUserToGroupResponse> responseObject 
                            = new AmazonServiceResult<AddUserToGroupRequest,AddUserToGroupResponse>((AddUserToGroupRequest)req, (AddUserToGroupResponse)res, ex , ao.State);    
                        callback(responseObject); 
                };
            BeginInvoke<AddUserToGroupRequest>(request, marshaller, unmarshaller, options, callbackHelper);
        }