code: function tweakWebpackConfig(module) {
    const { default: webpackConfig = module } = module;
  
    const config = handleWebpackConfig(webpackConfig);
  
    if (!config) {
      throw new Error(
        'Not found webpack configuration. For multiple configurations in single file you must provide config with target "node".'
      );
    }
  
    const hmrClientEntry = require.resolve('./HmrClient');
  
    const addHmrClientEntry = (entry, entryOwner) => {
      const owner = entryOwner;
      if (Array.isArray(owner[entry])) {
        owner[entry].splice(-1, 0, hmrClientEntry);
      } else if (typeof owner[entry] === 'string') {
        owner[entry] = [hmrClientEntry, owner[entry]];
      } else if (typeof owner[entry] === 'function') {
        // Call function and try again with function result.
        owner[entry] = owner[entry]();
        addHmrClientEntry(entry, owner);
      } else if (typeof owner[entry] === 'object') {
        Object.getOwnPropertyNames(owner[entry]).forEach(name =>
          addHmrClientEntry(name, owner[entry])
        );
      }
    };
  
    // Add HmrClient to every entries.
    addHmrClientEntry('entry', config);
  
    if (!config.plugins) {
      config.plugins = [];
    }
  
    // Add source-map support if configured.
    if (config.devtool && config.devtool.indexOf('source-map') >= 0) {
      config.plugins.push(
        new webpack.BannerPlugin({
          banner: `;require('${require
            .resolve('source-map-support')
            .replace(/\\/g, '/')}').install();`,
          raw: true,
          entryOnly: false,
        })
      );
    }
  
    // Enable HMR globally if not.
    if (!config.plugins.find(p => p instanceof webpack.HotModuleReplacementPlugin)) {
      config.plugins.push(new webpack.HotModuleReplacementPlugin());
    }
  
    return config;
  }
docs: Add hmrClient to all entries.
  @param module
  @returns {Promise.<config>}