How to use the midway.init function in midway

import { scope, ScopeEnum, provide, init, plugin } from 'midway';

const dataId = 'acm.test.1';
const group = 'DEFAULT_GROUP';

@provide()
@scope(ScopeEnum.Singleton)
export class ACMService {

  acmText;

  @plugin()
  acm;

  @init()
  async init() {
    // 放在这里是因为设置成了单例，全局只会有一份实例
    const str = `example_test_${Math.random()}_${Date.now()}`;
    await this.acm.publishSingle(dataId, group, str);

    this.acm.subscribe({
      dataId,
      group
    }, (data) => {
      console.log('get data from acm', data);
      this.acmText = data;
    });
    
    this.acmText = await this.acm.getConfig(dataId, group);
  }

const NacosNamingClient = require('nacos').NacosNamingClient;

@provide()
@scope(ScopeEnum.Singleton)
export class NamingService {

  nacosClient;

  @config('nacosNaming')
  nacosConfig;

  @logger()
  logger;

  @init()
  async init() {
    this.nacosClient = new NacosNamingClient({
      ...this.nacosConfig,
      logger: this.logger,
      namespace: 'public',
    });
    await this.nacosClient.ready();

    // 这里的服务名请从 nacos 服务上找
    this.nacosClient.subscribe('nacos.test.3', hosts => {
      console.log('-----------naming result start --------------');
      console.log(hosts);
      console.log('-----------naming result end--------------');
    });
  }

}

export interface IDB {
  sequelize: Sequelize;
  options: IDBOptions;
}
@scope(ScopeEnum.Singleton)
@async()
@provide('DB')
export default class DB implements IDB {
  public sequelize: Sequelize;

  @config('sequelize')
  public options: IDBOptions;

  @init()
  public connect() {
    this.sequelize = new Sequelize(
      this.options.database,
      this.options.username,
      this.options.password,
      {
        dialect: this.options.dialect,
        host: this.options.host,
        port: this.options.port,
        timezone: '+08:00',
        logging: false,
      },
    );
  }
}