[R-pkg-devel] unusually slow tests on win-builder

hi,

i've uploaded a version of my package to the win-builder service, but it 
is reporting that one of my tests takes > 10 seconds to run. examining 
the log here:

https://win-builder.r-project.org/BvR4nreDE9qP/00check.log

the win-builder is taking 24 and 28 seconds to run this test.

on my local machine, this same test runs in 600ms

can anyone shed any light on this? why is the win-builder so slow?

with thanks

jonathon