public void TestMultiReferencesBaggage()
        {
            MockTracer tracer = new MockTracer(Propagators.TextMap);
            MockSpan   parent = (MockSpan)tracer.BuildSpan("parent").Start();

            parent.SetBaggageItem("parent", "foo");
            MockSpan precedent = (MockSpan)tracer.BuildSpan("precedent").Start();

            precedent.SetBaggageItem("precedent", "bar");

            MockSpan followingSpan = (MockSpan)tracer.BuildSpan("follows")
                                     .AddReference(References.FollowsFrom, precedent.Context)
                                     .AsChildOf(parent.Context)
                                     .Start();

            Assert.Equal("foo", followingSpan.GetBaggageItem("parent"));
            Assert.Equal("bar", followingSpan.GetBaggageItem("precedent"));
        }