readFully(buffer); readFully(pad,0,((4 - len) & 3));
readFully(buffer,0,len); readFully(pad,0,(4 - len) & 3);
    public byte[] readBuffer() throws IOException {        int len = readInt();        byte[] buffer = new byte[len];        readFully(buffer);        readFully(pad,0,((4 - len) & 3));        return buffer;    }