text: 
  import { DataProvider } from '../../index';
  export default class C extends DataProvider {
      static deps = ['d'];
      prepare(ctx, params) {
          return params['d'];
      }
      execute(ctx, params) {
          return new Promise(resolve => {
              setTimeout(() => {
                  resolve('provider c');
              }, 1000);
          });
      }
  }