1.刚在mac电脑上安装了flutter，flutter doctor也ok了，在android studio 下下载了一个模拟器，然后执行flutter emulators 找到刚才创建的模拟器，再执行flutter emulators --launch <device name> ，再flutter run ，就报错:
终端执行如下:

wangydeMacBook-Pro:demo wangy$ flutter run
Using hardware rendering with device Android SDK built for x86. If you get graphics artifacts, consider enabling software rendering
with "--enable-software-rendering".
Launching lib/main.dart on Android SDK built for x86 in debug mode...
Initializing gradle...                                             98.5s
Resolving dependencies...                                           4.2s
Running Gradle task 'assembleDebug'...
Running Gradle task 'assembleDebug'... Done                         3.4s
Built build/app/outputs/apk/debug/app-debug.apk.
Error connecting to the service protocol: HttpException: Connection closed before full header was received, uri =
http://127.0.0.1:61366/GKYOILbC-3w=/ws