code: function nativeAsyncRequire(ids, callback, baseId) {
          var isCallbackCalled = 0;
  
          each(ids, function (id) {
              if (!(BUILDIN_MODULE[id] || modIs(id, MODULE_DEFINED))) {
                  modAddDefinedListener(id, tryFinishRequire);
                  (id.indexOf('!') > 0
                      ? loadResource
                      : loadModule
                  )(id, baseId);
              }
          });
          tryFinishRequire();
  
          /**
           * 尝试完成require，调用callback
           * 在模块与其依赖模块都加载完时调用
           *
           * @inner
           */
          function tryFinishRequire() {
              if (typeof callback === 'function' && !isCallbackCalled) {
                  var isAllCompleted = 1;
                  each(ids, function (id) {
                      if (!BUILDIN_MODULE[id]) {
                          return (isAllCompleted = !!modIs(id, MODULE_DEFINED));
                      }
                  });
  
                  // 检测并调用callback
                  if (isAllCompleted) {
                      isCallbackCalled = 1;
  
                      callback.apply(
                          global,
                          modGetModulesExports(ids, BUILDIN_MODULE)
                      );
                  }
              }
          }
      }
docs: 异步加载模块
  内部使用，模块ID必须是经过normalize的Top-Level ID
  
  @inner
  @param {Array} ids 模块名称或模块名称列表
  @param {Function=} callback 获取模块完成时的回调函数
  @param {string} baseId 基础id，用于当ids是relative id时的normalize