public async Task SetsKey()
        {
            string keyValue  = "test_key";
            string header    = "api_key";
            var    transport = new MockTransport(new MockResponse(200));
            var    keyPolicy = new AzureKeyCredentialPolicy(new AzureKeyCredential(keyValue), header);

            await SendGetRequest(transport, keyPolicy);

            Assert.True(transport.SingleRequest.TryGetHeader(header, out var key));
            Assert.AreEqual(key, keyValue);
        }
        public async Task VerifyRetry()
        {
            string keyValue  = "test_key";
            string header    = "api_key";
            var    transport = new MockTransport(new MockResponse(200), new MockResponse(200));
            var    keyPolicy = new AzureKeyCredentialPolicy(new AzureKeyCredential(keyValue), header);

            using (Request request = transport.CreateRequest())
            {
                request.Method = RequestMethod.Get;
                var pipeline = new HttpPipeline(transport, new[] { keyPolicy });
                await pipeline.SendRequestAsync(request, CancellationToken.None);

                await pipeline.SendRequestAsync(request, CancellationToken.None);
            }

            Assert.True(transport.Requests[0].TryGetHeader(header, out var key));
            Assert.AreEqual(key, keyValue);
        }