Fix dummy trasformer

encodings.go

@@ -30,6 +30,7 @@ type DummyTransformer struct{}
 func (e *DummyTransformer) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
 	copy(dst, src)
 
-	return len(dst), len(src), nil
+	return len(src), len(src), nil
 }
+
 func (e *DummyTransformer) Reset() {}