Waiting for another flutter comm

当运行flutter命令出现Waiting for another flutter command to release the startup lock...时：
Step 1:启动任务管理器（活动监视器for Mac OSX），找到dart进程，干掉；

Step 2：删除(your_flutter_directory/flutter/bin/cache/lockfile)

rm your_flutter_directory/flutter/bin/cache/lockfile

Done.