public static void UpdateActivityLogTask()
        {
            var binding = new BasicHttpBinding();
            binding.MaxReceivedMessageSize = Int32.MaxValue;

            var target = new bfsapi.bfsapiSoapClient(binding, new EndpointAddress("http://localhost:20010/bfsapi.asmx"));
            var req = new UpdateTaskRequest();
            req.Credentials = new bfsapi.Credentials
            {
                UserName = GetApiUserName(),
                Password = GetApiPassword()
            };

            req.identify = GetApiIdentifier();
            req.Fields=new UpdateTaskFields
            {
                Heading = true,
                Priority = true,
                CustomFields = true,
                DueDate = true
            };

            req.Entities = new[]
            {
                new bfsapi.UpdateTask()
                {
                    BrickId = new Guid("20b36672-0109-4679-ad7e-aed65494977d"),
                    Heading = "UpdatedeHeading",
                    Priority = "Medium",
                    CustomFields = new CustomField[]
                    {
                        new CustomField
                        {
                            FieldName = "TestFieldUpdate",
                            Value = "TestValueUpdate"
                        }, 
                    },
                    DueDate = DateTime.Today.AddDays(10)
                    
                }
            };

            var resp = target.UpdateTasks(req);
        }