一、Waiting for another flutter command to release the startup lock...
运行flutter命令 flutter upgrade
运行 flutter doctor 提示 如下错误
Waiting for another flutter command to release the startup lock...
查了一下github的flutter issue 找到了解决方法，如下：
1、打开flutter的安装目录/bin/cache/
2、删除lockfile文件
3、重启AndroidStudio
Windows下 删除 flutter的安装目录/bin/cache/
删除 dart-sdk.old 文件重新运行 升级命令 解决