parallelLibrary: Load packages for parallelization.
In parallelMap: Unified Interface to Parallelization Back-Ends

Makes sure that the packages are loaded in slave process so that they can be used in a job function which is later run with parallelMap().

For all modes, the packages are also (potentially) loaded on the master.

parallelLibrary(
  ...,
  packages,
  master = TRUE,
  level = NA_character_,
  show.info = NA
)

`...`	character Names of packages to load.
`packages`	(`character(1)`) Names of packages to load. Alternative way to pass arguments.
`master`	(`logical(1)`) Load packages also on master for any mode? Default is `TRUE`.
`level`	(`character(1)`) If a (non-missing) level is specified in `parallelStart()`, the function only loads the packages if the level specified here matches. See `parallelMap()`. Useful if this function is used in a package. Default is `NA`.
`show.info`	(`logical(1)`) Verbose output on console? Can be used to override setting from options / `parallelStart()`. Default is NA which means no overriding.