cb = function () {
	            currCall = (new Date()).getTime();
	            scope = this;
	            args = arguments;
	            var thisDelay = debounceNextCall || delay;
	            var thisDebounce = debounceNextCall || debounce;
	            debounceNextCall = null;
	            diff = currCall - (thisDebounce ? lastCall : lastExec) - thisDelay;

	            clearTimeout(timer);

	            if (thisDebounce) {
	                timer = setTimeout(exec, thisDelay);
	            }
	            else {
	                if (diff >= 0) {
	                    exec();
	                }
	                else {
	                    timer = setTimeout(exec, -diff);
	                }
	            }

	            lastCall = currCall;
	        }
Get zrender instance by id
@param {string} id zrender instance id
@return {module:zrender/ZRender}