requestEnd property for resource timing

hello, 

i have read the resource timing draft and i suggest to add the "requestEnd" attribute to the PerformanceEntry interface to be able to calculate the time the server needs to respond with the first byte. If you use the chrome developer tools and use the network tab you can see the "waiting" time which you could calculate from requestEnd and responseStart attributes. without the requestEnd attribute calculating the waiting time seems not to be possible.

thanks,

matthias