UPDATE: Add precheck version hdiff, support another hdiff

pkg/verifier/verifier.go

@@ -67,7 +67,7 @@ func check(relPath string, expectedSize int64, expectedMD5, base string) error {
 			fullPath, expectedSize, info.Size())
 	}
 
-	md5Hash, err := fileMD5(fullPath)
+	md5Hash, err := FileMD5(fullPath)
 	if err != nil {
 		return fmt.Errorf("error reading %s: %w", fullPath, err)
 	}
@@ -80,7 +80,7 @@ func check(relPath string, expectedSize int64, expectedMD5, base string) error {
 	return nil
 }
 
-func fileMD5(path string) (string, error) {
+func FileMD5(path string) (string, error) {
 	f, err := os.Open(path)
 	if err != nil {
 		return "", err