I've noticed this primarily when uploading MP4s of me reproing bugs to bugzilla. This does not always occur, but I've just had it happen first the first 2 attemps to for https://bugzilla.mozilla.org/show_bug.cgi?id=1595462#c7 which only worked on my 3rd upload attempt

STR:

• Navigate to the attach new file page for a bug on bugzilla.mozilla.org
• Select the file to upload by dragging and dropping it into the area indicated on the page.
• Click submit at the bottom of the dialog.
• Entire browser crashes.

Crash reports:

• https://crash-stats.mozilla.org/report/index/89f6995a-2368-470b-9578-b02810191113
• https://crash-stats.mozilla.org/report/index/0c682d7b-7257-416f-b35f-969930191113

Further notes:

• When the crash happens the file is not uploaded and I need to try again.
• It's not clear to me if the size or nature of the file matter, but I see this happen with video files of me reproing bugs that I produce with Open Boradcaster Software (OBS).
• I've only seen this on Windows as it's my primary dev platform.
• The stacks look networking related to me, but this is not my area of expertise so please reassign as required.

This involves DocumentChannelCreationArgs. Matt can you take a look?

Looks like the same issue as bug 1595578, I'll try get it fixed ASAP.