Use a HEAD instead of GET

... to retrieve only the headers of the resource without the body. This will save bandwidth and time.

pkg/sync/handler.go

@@ -34,7 +34,7 @@ func (h *HTTPHandler) GetSizeFromURL(url string) (size int64, err error) {
 	ctx, cancel := context.WithTimeout(context.Background(), types.HTTPTimeout)
 	defer cancel()
 
-	rr, err := http.NewRequestWithContext(ctx, "GET", url, nil)
+	rr, err := http.NewRequestWithContext(ctx, "HEAD", url, nil)
 	if err != nil {
 		return 0, err
 	}