How does vue mount the global shared method

For example, put echarts on the Vue prototype to facilitate the use
of vue2 writing

import Vue from 'vue'
Vue.prototype.$echarts = echarts

How to write vue3

import {
    
     createApp } from 'vue'
import App from './App.vue'
const app = createApp(App)
app.config.globalProperties.$echarts = echarts

Note that in the setup of vue3, it is no longer possible to directly use this.xxxx to use public methods like in vue2.
Use in vue3

 import {
    
     getCurrentInstance } from 'vue';
 const instance = getCurrentInstance();
 //使用全局方法
 instance.appContext.config.globalProperties