fix: proxyHandler — streaming с Flush, 64KB буфер

server/main.go

@@ -320,9 +320,30 @@ func proxyHandler(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/octet-stream")
 	w.Header().Set("Last-Modified", stat.LastModified.Format(http.TimeFormat))
 
-	if _, err := io.Copy(w, obj); err != nil {
+	buf := make([]byte, 64*1024) // 64KB buffer
-		log.Printf("Error streaming object: %v", err)
+	flusher, canFlush := w.(http.Flusher)
+	written := int64(0)
+	for {
+		n, readErr := obj.Read(buf)
+		if n > 0 {
+			nw, writeErr := w.Write(buf[:n])
+			if writeErr != nil {
+				log.Printf("Error writing response: %v", writeErr)
+				return
+			}
+			written += int64(nw)
+			if canFlush {
+				flusher.Flush()
+			}
+		}
+		if readErr != nil {
+			if readErr != io.EOF {
+				log.Printf("Error reading object: %v", readErr)
+			}
+			break
+		}
 	}
+	log.Printf("Proxy: sent %d/%d bytes for %s", written, stat.Size, key)
 }
 
 func discoveryHandler(w http.ResponseWriter, r *http.Request) {