public void sendMessage(byte[] data,int len) throws IOException {
  out.write(U.intToBytes(len));
  out.write(data,0,len);
}

public void sendMessage ( byte [ ] data , int len ) throws IOException { out . write ( U . intToBytes ( len ) ) ; out . write ( data , 0 , len ) ; }
send bytes over the socket prefixing them with the 4 - byte array size .
