anchor.diff:  
     tearDown(() async {
       await http2.close();
  +    await h1c.close();
     });
   
     test('buffered response', () async {
       var response = await client.get(serverRoot);
  +    expect(response.body, 'Hello world');
  +  });
  +
  +  test('allowHttp1', () async {
  +    var response = await h1c.get(serverRoot);
       expect(response.body, 'Hello world');
     });
   
  
positive.code:       ..usePrivateKey('dev.key', password: 'dartdart')
        ..setAlpnProtocols(['h2'], true);
  
      http2 = AngelHttp2(app, ctx);
  
      var server = await http2.startServer();
      serverRoot = Uri.parse('https://127.0.0.1:${server.port}');
  
negative.code: 
  void main() {
    var client = Http2Client();
    var h1c = http.Client();
    Angel app;
    AngelHttp2 http2;
    Uri serverRoot;
  