code: public void putback(byte[] bytes, int p, int n) {
          if (numTranscoders == 0 || n == 0) return;
          Transcoding transcoding = elements[0].transcoding;
          System.arraycopy(transcoding.readBuf, transcoding.recognizedLength + transcoding.readAgainLength - n, bytes, p, n);
          transcoding.readAgainLength -= n;
      }
docs: /* rb_econv_putback