Introduced Go module support as v4, removed obsolete CloseNotifier()
This reintroduces support for Go modules, as v4. Please see the README for compatibility.
CloseNotifier() is removed as it has been obsoleted, see https://golang.org/doc/go1.11#net/http
It was already NOT working (not sending signals) as of 1.11 the functionality was gone, we merely
deleted the functions that exposed it. If anyone still relies on it they should migrate to using
c.Request().Context().Done()
instead.