Fetch
The Fetch API provides an interface for asynchronously fetching resources via HTTP requests inside of a Worker.
The fetch method is implemented on the ServiceWorkerGlobalScope. Refer to MDN documentation for more information.
 Constructor
- fetch(request, init ):- Promise- <Response>- Fetch returns a promise to a Response.
 
 Parameters
- request- Request|- string- The Requestobject or a string represents the URL to fetch.
 
- The 
- init- RequestInit- The content of the request.