The question becomes: how does information get passed along to indicate
things that may take a long time to run. The discussion so far has focused
on developers setting, or using, some flags to indicate tests and examples
that take a long time. Another option would be to have the check/build
process generate a file with information about the time it took to run
tests, vignettes, and examples, probably with some information about the
speed of the machine it was run on. Then CRAN and anyone else that wants to
run tests can take this information into consideration.