Allow mod_esi:deliver/2 to handle binary data

[Bernard Duggan]

Hi all,
     We've been using mod_esi to deliver binary files over HTTP.  In 
testing, some particularly large files were thrown at it and we ended up 
exhausting the VM's memory and crashing it.  The ultimate problem is 
that mod_esi:deliver/2 is asynchronous, so there's no way to know how 
fast or slowly to feed it data to avoid the target process' queue 
getting too big.  That's a bit of a trickier problem than I could 
quickly deal with (not least because it would require an interface 
change/addition).
     Instead, to mitigate the problem I've made a small change which 
allows mod_esi:deliver/2 to take binary data, rather than forcing the 
caller to convert it to a list first (and thus avoiding both the 
conversion cost and the copy cost as the list is passed between processes).

You can grab it with

git fetch git://github.com/bernardd/otp.git mod_esi_binary

Cheers,

Bernard