1 检查配置
首先配置 pubspec.yaml，pubspec 里除了插件的依赖，可以根据需要，把这些补上：
name: flutter_plugin_20181225
description: A new Flutter plugin
version: 0.0.1
author: Joker <wrap****@gmail.com>
homepage: https://github.com/joker-fu
environment:
sdk: ">=1.19.0 <2.0.0"
发布到 Pub 上需要包含一个LICENSE, 我是把代码传到github生成一个，复制到根目录LICENSE里就好。
2 检查插件
flutter packages pub publish --dry-run
Terminal中输入以上命令，Terminal中显示Package has 0 warnings. 则无问题，否则根据提示修改即可。
3 发布插件（注意 番羽 墙）
flutter packages pub publish
Terminal中输入以上命令，第一次发布会出现以下授权界面，复制链接到浏览器授权即可
Looks great! Are you ready to upload your package (y/n)? y
Pub needs your authorization to upload packages on your behalf.
In a web browser, go to https://accounts.google.com/o/oauth2/auth?*******userinfo.email
Then click "Allow access".
注意： 链接到 .email 结束，直接点击userinfo.email可能未包含。
授权完后Android Studio自动开始上传插件，当Terminal中显示Package has 0 warnings. 则无问题，否则根据提示修改即可。
Waiting for your authorization...
Authorization received, processing...
It looks like accounts.google.com is having some trouble.
Pub will wait for a while before trying to connect again.
OS Error: Operation timed out, errno = 60, address = accounts.google.com, port = 53481
pub finished with exit code 69
出现上面这个证明还要 番羽 墙，这时在Android Studio中系统设置的配置的HTTP Proxy可能你CHeck connection是有效的，但是还是会出现以上问题，需要在Terminal中输入以下命令，重新执行本步骤即可。
//我这里是SS，不同的工具可能不一样。
set http_proxy=http://127.0.0.1:1080
set https_proxy=https://127.0.0.1:1080
