/** {@inheritDoc} */
 @Override
 public byte[] writeLine(KeyValuePair<PactNull, PactString> pair) {
   String value = pair.getValue().toString();
   String line = value + "\n";
   return line.getBytes();
 }
 /** {@inheritDoc} */
 @Override
 public boolean readLine(KeyValuePair<PactNull, PactString> pair, byte[] line) {
   pair.setKey(new PactNull());
   pair.setValue(new PactString(new String(line)));
   return true;
 }