I have a site running apache whose main purpose in life is to serve up large (10-30 Mb) pdf files. I get emails fairly frequently from users saying that they're having problems downloading the files:
"will start to download, but the download doesn't complete, it freezes at about 25%."
"It seems to find the page, but just spins and spins ... I let it go 5 min. No data. HOWEVER: When I chose "download" I got it in seconds."
"It somehow starts loading the pdf at around 10%, both in Chrome and Firefox."
Since I can't reproduce the problems, and they don't seem to occur for the vast majority of users, it's very hard to figure out what's up. Presumably the users have misconfigured their browsers or plugins somehow, or maybe in some cases it's a usability issue with their browser or plugin. Getting users to report specific error messages or behavior, describe their configuration, etc., is like pulling teeth.
I've seen some other questions that describe similar problems, but they seem specific to IIS, whereas I'm running apache:
This bug doesn't seem to match the (vague) reports I've gotten:
If anyone would like to try to reproduce the error, a pdf for which users have reported problems is here: http://www.lightandmatter.com/sr/sr.pdf [It may now be impossible to reproduce the behavior because I've implemented Håkan Lindqvist's answer.]