calls++;
    void runAsync (String method, Vector params, AsyncCallback callback) {	Object res = null;	long start = System.currentTimeMillis ();	try {	    res = execute (method, params);	    // notify callback object	    if (callback != null)	        callback.handleResult (res, url, method);	} catch (Exception x) {                 if (callback != null)	        callback.handleError (x, url, method);	}	calls++;	long end = System.currentTimeMillis ();	roundtrip = (int) ((roundtrip*4)+(end-start))/5;    }