Ok... I made an earlier post regarding this question, I got an answer (which I haven't completely implemented because I don't understand how to configure it as extension), but in the process I learned that this is actually working with Firefox and I don't know why.
Somehow, Firefox is requesting the content range and without any code change on my side, IIS (or something) is sending the proper continued stream, while IE doesn't seem to recognize that it can pause / resume even though I'm setting the required header information and the requests / responses look identical when inspected using Wireshark.
So, my bigger question is how or what is sending the partial file, if my code is not? Is this built into .net? I removed the Etag stuff when I noticed this was working in Firefox and hard coded the modified date.< ...
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