public void ProcessOperatorCircleCircumference()
        {
            var a           = 1.5f;
            var value_a     = new VFXValue <float>(a);
            var expressionA = VFXOperatorUtility.CircleCircumference(value_a);

            var context           = new VFXExpression.Context(VFXExpressionContextOption.CPUEvaluation);
            var resultExpressionA = context.Compile(expressionA);

            Assert.AreEqual(a * 2.0f * Mathf.PI, resultExpressionA.Get <float>(), 0.001f);
        }