Fetch Handler
 Background
Incoming HTTP requests to a Worker are passed to the fetch() handler as a Request object. To respond to the request with a response, return a Response object:
export default {	async fetch(request, env, ctx) {		return new Response('Hello World!');	},
};
 Parameters
- request- Request- The incoming HTTP request.
 
- env- object- The bindings available to the Worker. As long as the environment has not changed, the same object (equal by identity) may be passed to multiple requests.
 
- ctx.waitUntil(promisePromise):- void- Refer to waitUntil.
 
- Refer to 
- ctx.passThroughOnException():- void- Refer to passThroughOnException.
 
- Refer to