the initial guineapig.

We have a number of pools of objects we maintain dynamically and we
will get more in the future, so having a generic facility makes sense.

One particular aspect of some of our pools, is that the desired size
of object is variable over time, for instance workspaces which
depend on parameters etc.

Using generic code will allow us to use systematic parameters and
VSC stats for all pools, hopefully with some memory savings involved.