assert source != null && dest != null : "source or dest cannot be null for an off chip buffer";
    protected OffChipBuffer(TraceNode source, TraceNode dest)    {	if ((source.isFilterTrace() && !dest.isOutputTrace()) ||	    (source.isOutputTrace() && !dest.isInputTrace()) ||	    (source.isInputTrace() && !dest.isFilterTrace()))	    Utils.fail("invalid buffer type");		this.source = source;	this.dest = dest;	users = new Vector();	ident = "__buf_" + /*owner.getIODevice().getPort() + */ "_" + unique_id + "__";	unique_id++;	setType();	calculateSize();    }