Adding a request scoped ram:// drive

There are some problems with ram drives and java gc with the soft references sometimes breaking the ram drive completely, requiring a server restart before it works again. https://luceeserver.atlassian.net/browse/LDEV-1109

Thinking about this problem, I had the idea of having a ram drive available per request, instead of per context. something like requestRam://file.txt or even just request://file.txt which obviously could apply to session and application…

As the request ram drive would be automatically purged after the request is finished, this would help avoid the gc problems. I’m guessing quite a lot of use cases for this are just doing temp file operations in a single request.