public void SetDelegateArgument()
        {
            // for using delegate argument

            TheStruct valueType             = new TheStruct();
            int       indiceValue           = 2;
            DelegateInArgument <int> indice = new DelegateInArgument <int>();
            Variable <TheStruct>     var    = VariableHelper.CreateInitialized <TheStruct>("var", valueType);
            TestValueTypeIndexerReference <TheStruct, int> valueTypeIndexerReference = new TestValueTypeIndexerReference <TheStruct, int>()
            {
                OperandLocationVariable = var,
            };

            valueTypeIndexerReference.Indices.Add(new TestArgument <int>(Direction.In, null, (env) => indice.Get(env)));

            int value = 321;
            TestAssign <int> testAssign = new TestAssign <int>()
            {
                ToLocation = valueTypeIndexerReference, Value = value
            };

            TestSequence seq = new TestSequence()
            {
                Activities =
                {
                    testAssign,
                    new TestWriteLine {
                        MessageExpression = ((ctx) => var.Get(ctx)[indiceValue].ToString())
                    }
                }
            };

            CoreWf.Statements.Sequence outerSeq = new CoreWf.Statements.Sequence()
            {
                Variables =
                {
                    var
                },
                Activities =
                {
                    new InvokeAction <int>()
                    {
                        Argument = indiceValue,
                        Action   = new ActivityAction <int>()
                        {
                            Argument = indice,
                            Handler  = seq.ProductActivity
                        }
                    }
                }
            };

            TestCustomActivity testActivity = TestCustomActivity <CoreWf.Statements.Sequence> .CreateFromProduct(outerSeq);

            UnorderedTraces traces = new UnorderedTraces()
            {
                Steps =
                {
                    new UserTrace(value.ToString())
                }
            };

            testActivity.ActivitySpecificTraces.Add(traces);
            ExpectedTrace expectedTrace = testActivity.GetExpectedTrace();

            expectedTrace.AddIgnoreTypes(typeof(ActivityTrace));

            TestRuntime.RunAndValidateWorkflow(testActivity, expectedTrace);
        }