Profile usage of the ring buffer under real app conditions to decided default size

[grgustaf]

We need to make the ring buffer size easily configurable by the user, so like move that up to some global place where they'll look for a few key tunables.

The original patch had a 4KB buffer, the latest has a 1KB buffer. We don't really know how much is needed for our current samples or for real apps that will be written. So we should attempt to profile what might really be needed to set a good default. But again ultimately the user may want to increase this an app with tons of callback activity that can queue up, or decrease it if memory is too scarce.