inputStream = new PushbackInputStream(is, pushBackSize);
outputStream = os;
break;
case 1:
// monitor con coda unica condivisa
MonitorStreamQueue mq = new MonitorStreamQueue();
inputStream = new PushbackInputStream(new MonitorInputStream(is, mq), pushBackSize);
outputStream = new MonitorOutputStream(os, mq);
inputQueue = outputQueue = mq;
break;
case 2: