╰─➤  rm $FH/flutter/bin/cache/flutter_tools.s* && $FH/flutter/bin/flutter drive --debug --preview-dart-2 test_driver/scroll_perf.dart
Building flutter tool...
Running "flutter packages get" in complex_layout...   0.6s
Using device Nexus 5.
Starting application: test_driver/scroll_perf.dart
Initializing gradle...                                0.8s
Resolving dependencies...                             0.7s
Installing build/app/outputs/apk/app.apk...          11.8s
Running 'gradlew assembleDebug'...                   10.3s
Built build/app/outputs/apk/debug/app-debug.apk (33.6MB).
Installing build/app/outputs/apk/app.apk...          11.5s
I/FlutterActivityDelegate(26449): onResume setting current activity to this
I/flutter (26449): Observatory listening on http://127.0.0.1:54802/
00:00 +0: scrolling performance test (setUpAll)
[info ] FlutterDriver: Connecting to Flutter application at http://127.0.0.1:8104/
[trace] FlutterDriver: Looking for the isolate
[trace] FlutterDriver: Isolate is paused at start.
[trace] FlutterDriver: Attempting to resume isolate
[trace] FlutterDriver: Waiting for service extension
E/flutter (26449): [ERROR:topaz/lib/tonic/logging/dart_error.cc(16)] Unhandled exception:
E/flutter (26449): type '(Map<String, String>) => Future<Map<String, dynamic>>' is not a subtype of type '(Map<String, String>) => Future<Map<String, String>>'
E/flutter (26449): #0      _DriverBinding.initServiceExtensions (package:flutter_driver/src/extension/extension.dart:49:27)
E/flutter (26449): #1      new BindingBase (package:flutter/src/foundation/binding.dart:55:5)
E/flutter (26449): #2      new _BindingBase&ServicesBinding (package:flutter_driver/src/extension/extension.dart)
E/flutter (26449): #3      new __BindingBase&ServicesBinding&SchedulerBinding (package:flutter_driver/src/extension/extension.dart)
E/flutter (26449): #4      new ___BindingBase&ServicesBinding&SchedulerBinding&GestureBinding (package:flutter_driver/src/extension/extension.dart)
E/flutter (26449): #5      new ____BindingBase&ServicesBinding&SchedulerBinding&GestureBinding&PaintingBinding (package:flutter_driver/src/extension/extension.dart)
E/flutter (26449): #6      new _____BindingBase&ServicesBinding&SchedulerBinding&GestureBinding&PaintingBinding&RendererBinding (package:flutter_driver/src/extension/extension.dart)
E/flutter (26449): #7      new ______BindingBase&ServicesBinding&SchedulerBinding&GestureBinding&PaintingBinding&RendererBinding&WidgetsBinding (package:flutter_driver/src/extension/extension.dart)
E/flutter (26449): #8      new _DriverBinding (package:flutter_driver/src/extension/extension.dart)
E/flutter (26449): #9      enableFlutterDriverExtension (package:flutter_driver/src/extension/extension.dart:66:7)
E/flutter (26449): #10     main (file:$FH/flutter/dev/benchmarks/complex_layout/test_driver/scroll_perf.dart:9:3)
E/flutter (26449): #11     _startIsolate.<anonymous closure> (dart:isolate/isolate_patch.dart:279:19)
E/flutter (26449): #12     _RawReceivePortImpl._handleMessage (dart:isolate/isolate_patch.dart:165:12)