Chrome Version       : 69.0.3497.81
OS Version: OS X 10.12.6
URLs (if applicable) :
Other browsers tested:
  Add OK or FAIL after other browsers where you have tested this issue:
     Safari: N/A
    Firefox: N/A
    IE/Edge: N/A

What steps will reproduce the problem?
1. (optional) Write devtools extension code that displays request.timings.receive for an asset
2. Hit a web page with images
3. Copy the HAR from the net tab, examine results from the extension, examine the Net tab, compare them for an image asset.

What is the expected result?

request.timings.receive should match "Content Download" time in the Timing tab in the network request detail. The HAR matches request.timings.receive.

What happens instead of that?

For SOME assets (not all) request.timings.receive appears to include the Queueing time along with the content download time. In my testing, this seemed to occur on JPG images, but not on text files. For text files I looked at request.timings.receive matched the Content Download number. 

Please provide any additional information below. Attach a screenshot if
possible. I'll attach a screenshot showing the net tab/Timings, and another showing a spreadsheet with the output from the extension.  Here is a snipped portion of the har for that resource (headers and cookies redacted):

{
	"startedDateTime": "2018-09-06T21:50:01.129Z",
	"time": 582.291177001287,
	"request": {
	  "method": "GET",
	  "url": "https://www.ballarddesigns.com/wcsstore/images/BallardDesigns/espots/2018/ma18/nav-banners/021618_MA18_Nav_espot_sunbrella.jpg",
	  "httpVersion": "HTTP/1.1",
	  "headers": [...],
	  "queryString": [],
	  "cookies": [...],
	  "headersSize": 3009,
	  "bodySize": 0
	},
	"response": {
	  "status": 200,
	  "statusText": "OK",
	  "httpVersion": "HTTP/1.1",
	  "headers": [...],
	  "cookies": [],
	  "content": {
		"size": 19129,
		"mimeType": "image/jpeg",
		"compression": 0
	  },
	  "redirectURL": "",
	  "headersSize": 1916,
	  "bodySize": 19129,
	  "_transferSize": 21045
	},
	"cache": {},
	"timings": {
	  "blocked": 31.711177000002703,
	  "dns": -1,
	  "ssl": -1,
	  "connect": -1,
	  "send": 0.07900000000000063,
	  "wait": 60.74399999827426,
	  "receive": 489.75700000301003,
	  "_blocked_queueing": 487.1770000027027
	},
	"serverIPAddress": "127.0.0.1",
	"connection": "118867",
	"pageref": "page_14"
}      

Note the receive time of 489.757, which matches request.timings.receive in the spreadsheet screenshot, but does not match "Content Download" (2.58) in the net tab screenshot.

Also, note that this equation from W3C HAR spec would not be satisfied with the data in the above HAR:

entry.time == entry.timings.blocked + entry.timings.dns +
    entry.timings.connect + entry.timings.send + entry.timings.wait +
    entry.timings.receive;

though if you exclude "_blocked_queueing" it does match, indicating that it is doubly included (my theory being that it is incorrectly included in the receive number).

UserAgentString: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.81 Safari/537.36



 

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