Flutter 进阶：创建动态水波纹进度环

Extension Discovery Cache ========================= This folder is used by `package:extension_discovery` to cache lists of packages that contains extensions for other packages. DO NOT USE THIS FOLDER ---------------------- * Do not read (or rely) the contents of this folder. * Do write to this folder. If you're interested in the lists of extensions stored in this folder use the API offered by package `extension_discovery` to get this information. If this package doesn't work for your use-case, then don't try to read the contents of this folder. It may change, and will not remain stable. Use package `extension_discovery` --------------------------------- If you want to access information from this folder. Feel free to delete this folder ------------------------------- Files in this folder act as a cache, and the cache is discarded if the files are older than the modification time of `.dart_tool/package_config.json`. Hence, it should never be necessary to clear this cache manually, if you find a need to do please file a bug.