L7 依赖高德地图，目前高德地图只支持在线引入，因此在react使用L7需要动态加载 高德jsapi, jsapi加载完成后再进行L7 scene初始化。
使用之前切记将本示例的高德地图key，设置成自己的。
const MAPKEY=""
In the project directory, you can run:
Runs the app in the development mode.
Open http://localhost:3000 to view it in the browser.
The page will reload if you make edits.
You will also see any lint errors in the console.
Launches the test runner in the interactive watch mode.
See the section about running tests for more information.
Builds the app for production to the build folder.
It correctly bundles React in production mode and optimizes the build for the best performance.
The build is minified and the filenames include the hashes.
Your app is ready to be deployed!
See the section about deployment for more information.