Returns the configured package cache directory without creating it.
Value
A length-one character vector containing the normalized cache path.
Details
The default is a session-temporary directory so routine package calls do not
write to the user's home directory. Set options(bluertopo.cache_dir = ...)
when a persistent cache is wanted.
Examples
bluertopo_cache_dir()
#> [1] "/tmp/RtmpUAcVpZ/bluertopo-cache"
