Fetch performs a GET request on provided string with timeout of 5 seconds. If response's
status code is in the range from 200 to 300 it returns it's Body. It's up to the user to close it
once finished using it.
Reachable performs HEAD request on provided URL and checks the status code. If it's 200 it'll
return `true` and status code. In any other case it'll return `false` adn status code 0.