if (pdu == null) { // only if we didn't manage to get pdu from unproc
buffer = connection.receive();
unprocBuffer = unprocessed.getUnprocessed();
// if received something now or have something from the last receive
if (buffer.length() != 0) {
unprocBuffer.appendBuffer(buffer);
unprocessed.setLastTimeReceived();
pdu = tryGetUnprocessedPDU(unprocessed);
} else {
debug.write(DRXTXD2, "no data received this time.");
// check if it's not too long since we received any data