canceling calls would cause the shared HTTP/2 connection to be unnecessarily released. This
    harmed connection reuse.
 *  Fix: Ensure canceled and discarded HTTP/2 data is not permanently counted against the limited
    flow control window. We had a few bugs where window size accounting was broken when streams
    were canceled or reset.
 *  Fix: Recover gracefully if the TLS session returns an unexpected version (`NONE`) or cipher

	walkMu     *sync.Mutex
	walkReadMu *sync.Mutex
}

// checkPathLength - returns error if given path name length more than 255
func checkPathLength(pathName string) error {
	// Apple OS X path length is limited to 1016
	if runtime.GOOS == "darwin" && len(pathName) > 1016 {
		return errFileNameTooLong
	}

	// Disallow more than 1024 characters on windows, there
	// are no known name_max limits on Windows.