Pings are being sent out of order

[st3fan]

I am seeing this in my stub telemetry endpoint. The small number at the end is the sequence number.

2018/04/18 17:20:40 127.0.0.1:57160       200 BDF44A4B-9146-45B8-9589-4233AB681373 core           / D2F01E77-9AE2-4470-BE33-7FE34E3A5C3F 2018-04-18           30 (21h20m40.075799823s)
2018/04/18 17:20:40 127.0.0.1:57160       200 29A4F388-1D4E-4BA8-B26C-C85E83DC25C3 mobile-event   / D2F01E77-9AE2-4470-BE33-7FE34E3A5C3F 1524086390150        16 (50.077320487s)
2018/04/18 17:20:46 127.0.0.1:57160       200 A697814C-4C04-4363-AEC8-043684E9BCE1 mobile-event   / D2F01E77-9AE2-4470-BE33-7FE34E3A5C3F 1524086413804        17 (33.721529514s)
2018/04/18 17:20:46 127.0.0.1:57160       200 9BEA4A9C-02B3-4DC0-B3C1-50944FCE0683 core           / D2F01E77-9AE2-4470-BE33-7FE34E3A5C3F 2018-04-18           32 (21h20m46.722728702s)
2018/04/18 17:20:46 127.0.0.1:57160       200 AD7A2EE5-8A93-46A6-87BE-52C662AD4681 core           / D2F01E77-9AE2-4470-BE33-7FE34E3A5C3F 2018-04-18           31 (21h20m46.734530224s)
2018/04/18 17:20:46 127.0.0.1:57160       200 67333AC0-811E-47D7-8EDF-2DBF1E93E21C core           / D2F01E77-9AE2-4470-BE33-7FE34E3A5C3F 2018-04-18           34 (21h20m46.743627433s)
2018/04/18 17:20:46 127.0.0.1:57160       200 69F7FF76-BC4B-4E73-9E52-49CD62E5F7CC core           / D2F01E77-9AE2-4470-BE33-7FE34E3A5C3F 2018-04-18           33 (21h20m46.753522224s)

Should we sort the outgoing queue before we start sending it?

[st3fan]

This is really easy to reproduce:

• Enable Airplane mode
• Foreground/Background Firefox a couple of times
• Disable Airplane mode
• Foreground Firefox when you have a network connection again

You will see the pings going out, in sort of random order. At least I do not see a patter:

29 (event)
60 (core)
28 (event)
57 (core)
61 (core)
58 (core)
62 (core)
69 (core)

[justindarc]

We're using a FileManager.DirectoryEnumerator to iterate over the stored pings. This is likely why they're going out-of-order. Looking at the docs now, it doesn't seem like there's any way to guarantee order. This may be a slightly larger code change to fix.