public async void NoClientIdentifierInHeaders()
        {
            // Given
            var context  = new DefaultHttpContext();
            var provider = new HeaderBasedClientIdentifierProvider();

            // When header-based client identifier provider is executed
            var result = await provider.ExecuteAsync(context);

            // Then it should return null identifier
            result.Should().BeNull();
        }
        public async void ClientIdentifierSetUsingCustomHeader()
        {
            // Given
            const string HeaderName = "my-custom-header";
            const string ClientId   = "tester";

            var provider = new HeaderBasedClientIdentifierProvider(HeaderName);
            var context  = new DefaultHttpContext();

            context.Request.Headers.Add(HeaderName, ClientId);

            // When header-based client identifier provider is executed
            var result = await provider.ExecuteAsync(context);

            // Then it should return the expected client identifier
            result.Should().Be(ClientId);
        }