code: function createHook(handler) {
      return function nodeDevHook(module, filename) {
        if (module.parent === wrapper) {
          // If the main module is required conceal the wrapper
          module.id = '.';
          module.parent = null;
          process.mainModule = module;
        }
        if (!module.loaded) callback(module.filename);
  
        // Invoke the original handler
        handler(module, filename);
  
        // Make sure the module did not hijack the handler
        updateHooks();
      };
    }
docs: Returns a function that can be put into `require.extensions` in order to
  invoke the callback when a module is required for the first time.