response.header("Pragma", "no-cache");
        response.header("Cache-Control", "no-cache");
        response.header("Expires", "Thu, 01 Dec 1994 16:00:00 GMT");
        response.contentTypeOctetStream();
        return response.stream(out -> {
            try {
                downloadObject(getObjectName(pi.getPath(), pi.getName()), out);

        response.header("Pragma", "no-cache");
        response.header("Cache-Control", "no-cache");
        response.header("Expires", "Thu, 01 Dec 1994 16:00:00 GMT");
    }

    /**
     * Writes content disposition header with filename.
     *
     * @param response the stream response
     * @param responseData the response data
     */

	// type of i is int
	// type of s is string
	// s == a[i]
	g(i, s)
}

var key string
var val interface{}  // element type of m is assignable to val
m := map[string]int{"mon":0, "tue":1, "wed":2, "thu":3, "fri":4, "sat":5, "sun":6}
for key, val = range m {
	h(key, val)
}
// key == last map key encountered in iteration
// val == map[key]

var ch chan Work = producer()
for w := range ch {