When I use NSURLSessionTaskTransactionMetrics property domainLookupStartDate and domainLookupEndDate to calculate the duration of DNS, sometimes I get 4294893875545978 or -4294893875545978 return
method like this
[NSNumber numberWithLongLong:[taskMetrics.domainLookupEndDate timeIntervalSinceDate:taskMetrics.domainLookupStartDate?]*1000000000]
The hexadecimal value of 4294893875545978 is 0xF3F3F3F3F3F3A. Is 4294893875545978 a special value？
supplement： This number will be stored in the sqlite database and then read out and uploaded. So, what could have gone wrong?
New findings, involves NSURLSessionTaskTransactionMetrics domainLookupStartDate
[NSNumber numberWithLongLong：[taskMetrics.domainLookupEndDate timeIntervalSinceDate：taskMetrics.responseStartDate]*1e9] also has this problem
The hexadecimal value of 4294893875545978 is 0xF3F3F3F3F3F3A.
Is it? That’s not what I calculate:
(lldb) p/x 4294893875545978
(long) 0x000f422ee7ccc77a
(lldb) p/x -4294893875545978
(long) 0xfff0bdd118333886
I’m not entirely sure what’s going on with your code but I do have one hint to pass along: Both domainLookupStartDate and domainLookupEndDate can be nil, so you should only run this calculation if both values are valid.
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