[ResourceTiming] Missing size property

Hello!

The "Resource Timing" standard (working draft) is very interesting and I
hope it will be soon implemented by many web browsers,
but I'm missing an essential data property for each loaded resource: the *
size* of the resource (in bytes) that is loaded!
The performance timing values would be much more meaningful if you know how
big the file was that was loaded so you can interpret if the network is the
bottleneck or if the file is really too big (e.g.: compress the image to
reduce the size).
(Or is there another possibility to get the file size of those measured
resources from JavaScript?)

So it would help many people to add a size attribute additional to the
existing resource description attributes of *type *and *url*:

readonly attribute unsigned short type
<http://w3c-test.org/webperf/specs/ResourceTiming/#type>;
readonly attribute DOMString url
<http://w3c-test.org/webperf/specs/ResourceTiming/#url>;*+ readonly
attribute unsigned long long size;*      // file size in Bytes


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Do you know when the first web browser will implement the resource timing
interface? (IE10?, Chrome, Firefox 6?, ...)

Kind regards,
Klaus Pesendorfer.