Bugfix: fast path for empty magic

protocol/match.go

@@ -9,6 +9,9 @@ package protocol
 //
 // Returns true if all magic bytes are matched, even if input has extra bytes.
 func Match(magic string, input []byte) bool {
+	if len(magic) == 0 {
+		return true
+	}
 	return match(magic, input, 0, 0)
 }