move to unawaited

pkgs/cupertino_http/example/integration_test/client_test.dart

@@ -2,6 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:async';
 import 'dart:io';
 import 'dart:typed_data';
 
@@ -46,7 +47,7 @@ void testClient(Client client) {
       }
       final request = StreamedRequest('POST', uri);
       request.sink.add(data);
-      await request.sink.close();
+      unawaited(request.sink.close());
       await client.send(request);
       expect(serverHash, sha1.convert(data).bytes);
     });