public override void ApplyAttributeBuilder(Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
        {
            if (a.Target == AttributeTargets.ReturnValue)
            {
                if (return_attributes == null)
                {
                    return_attributes = new ReturnParameter(this, InvokeBuilder.MethodBuilder, Location);
                }

                return_attributes.ApplyAttributeBuilder(a, ctor, cdata, pa);
                return;
            }

            base.ApplyAttributeBuilder(a, ctor, cdata, pa);
        }