Internal function - generic downloader, used to serve the rds files from S3

The function utilizes environment variable RCZECHIA_MIRROR as a mirror location of remote files; to configure an alternative (possibly local) repository use Sys.setenv("RCZECHIA_MIRROR" = "file:///someplace/local")

Usage

.downloader(file)

Arguments

file

file to be downloaded (or not...) from S3