Getting statistics out of hdPrman

Hi everyone,
Has anyone managed to get rendering statistics out of hdPrman? I have found the HdRenderDelegate::GetRenderStats virtual method but this doesn’t seem to be implemented for the render delegate, looking at the source in the USD repo. Is there an alternative solution?
Specifically I’m after a “progress” statistic to give some indication of how close to convergence the render is.

TIA