abstract void sendBuffer ();
protected void waitForRead () {
if (buffer.remaining () > 0)
readStartPos = buffer.position ();
SocketHandler sh = new Reader ();
HandlerRegistration hr = new HandlerRegistration (sh);
SocketChannel c = con.getChannel ();
try {
sk = c.register (con.getSelector (), SelectionKey.OP_READ, hr);
} catch (IOException e) {