Add support for rar extraction

pkg/http/client.go

@@ -328,20 +328,10 @@ func (r *HTTPClient) CanFetchFirstByte(url string) bool {
 	ctx, cancel := context.WithTimeout(context.Background(), timeout)
 	defer cancel()
 	req = req.WithContext(ctx)
-
-	resp, err := r.Do(req)
-	if err != nil {
-		return false
-	}
-	defer resp.Body.Close()
-
-	// If server supports partial content
-	if resp.StatusCode/100 == 2 {
-		buffer := make([]byte, 1)
-		_, err = resp.Body.Read(buffer)
-		if err == nil {
-			return true
-		}
+	resp, _ := r.Do(req)
+	if resp != nil {
+		defer resp.Body.Close()
+		return resp.StatusCode == 200 || resp.StatusCode == 206
 	}
 	return false
 }