Issue 1:
command

flutter build apk

exception

FormatException: FormatException: Bad UTF-8 encoding 0xbe (at offset 0)

#0 _Utf8Decoder.convert (dart:convert/utf.dart:574)
#1 _Utf8ConversionSink.addSlice (dart:convert/string_conversion.dart:345)
#2 _Utf8ConversionSink.add (dart:convert/string_conversion.dart:341)
#3 _ConverterStreamEventSink.add (dart:convert/chunked_conversion.dart:86)
#4 _SinkTransformerStreamSubscription._handleData (dart:async/stream_transformers.dart:120)
#5 _rootRunUnary (dart:async/zone.dart:1134)
#6 _CustomZone.runUnary (dart:async/zone.dart:1031)
#7 _CustomZone.runUnaryGuarded (dart:async/zone.dart:933)
#8 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:330)
#9 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:257)
#10 _StreamController&&_SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:763)
#11 _StreamController._add (dart:async/stream_controller.dart:639)
#12 _StreamController.add (dart:async/stream_controller.dart:585)
#13 _Socket._onData (dart:io-patch/socket_patch.dart:1654)
#14 _rootRunUnary (dart:async/zone.dart:1138)
#15 _CustomZone.runUnary (dart:async/zone.dart:1031)
#16 _CustomZone.runUnaryGuarded (dart:async/zone.dart:933)
#17 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:330)
#18 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:257)
#19 _StreamController&&_SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:763)
#20 _StreamController._add (dart:async/stream_controller.dart:639)
#21 _StreamController.add (dart:async/stream_controller.dart:585)
#22 new _RawSocket.<anonymous closure> (dart:io-patch/socket_patch.dart:1231)
#23 _NativeSocket.issueReadEvent.issue (dart:io-patch/socket_patch.dart:784)
#24 _microtaskLoop (dart:async/schedule_microtask.dart:41)
#25 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50)
#26 _runPendingImmediateCallback (dart:isolate-patch/dart:isolate/isolate_patch.dart:113)
#27 _RawReceivePortImpl._handleMessage (dart:isolate-patch/dart:isolate/isolate_patch.dart:166)

flutter doctor

[✓] Flutter (Channel beta, v0.1.5, on Microsoft Windows [Version 10.0.16299.125], locale zh-CN)
• Flutter version 0.1.5 at H:\google\flutter
• Framework revision 3ea4d06340 (2 weeks ago), 2018-02-22 11:12:39 -0800
• Engine revision ead227f118
• Dart version 2.0.0-dev.28.0.flutter-0b4f01f759

[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)
• Android SDK at H:\android-sdk
• Android NDK at H:\android-sdk\ndk-bundle
• Platform android-27, build-tools 27.0.3
• ANDROID_HOME = H:\android-sdk
• Java binary at: H:\Android Studio\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b01)

[✓] Android Studio (version 3.0)
• Android Studio at H:\Android Studio
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b01)

[✓] IntelliJ IDEA Ultimate Edition (version 2017.2)
• Flutter plugin version 21.2.2
• Dart plugin version 172.4343.25

[✓] Connected devices (1 available)
• MIX 2 • 356a5f19 • android-arm64 • Android 8.0.0 (API 26)

• No issues found!

Run this "flutter build apk" on PowerShell without this error

Issue 2:
I have a bottomsheet, and it contains a Listview which shows comment list. The comment List can be scroll, but when I scroll to the top of the list, I can not trigger the pull down to dismiss event even add the physics: ScrollPhysics .