Parallel processing on Windows when stepwise=FALSE

[aadler]

The documentation states that the packages uses mclapply for parallel processing of models when stepwise = FALSE, which of course does not work on Windows. Given that the future.apply package exists on CRAN and allows for a more uniform treatment of parallelism across operating systems, is there any possibility of converting the mechanics to a form of future_*apply which would work on Windows too?

[m-muecke]

Switching to future / mirai model would cause a breaking change, since in that model the caller owns the parallelism instead of the function. We discussed this a while back in the following PR: #1033. For now we could move to the makeCluster/clusterApplyLB interface that also works on Windows and doesn't cause a breaking change, which is also what the other functions do right now.