public void GetStatusCode_ReturnsExpected()
        {
            var options  = new MetricsObserverOptions();
            var stats    = new TestOpenTelemetryMetrics();
            var observer = new HttpClientCoreObserver(options, stats, null);

            var message = GetHttpResponseMessage(HttpStatusCode.OK);
            var status  = observer.GetStatusCode(message, default);

            Assert.Equal("200", status);

            status = observer.GetStatusCode(null, TaskStatus.Canceled);
            Assert.Equal("CLIENT_CANCELED", status);

            status = observer.GetStatusCode(null, TaskStatus.Faulted);
            Assert.Equal("CLIENT_FAULT", status);

            status = observer.GetStatusCode(null, TaskStatus.RanToCompletion);
            Assert.Equal("CLIENT_ERROR", status);
        }