checkdb_down downloads from CRAN the file check_results.rds, saves
it unchanged in the designated directory, by default in the current directory,
then loads it in .GlobalEnv under the name checkdb. checkdb is
a data.frame of dimension 200000 x 10 (approximatavely).
checkdb_load loads the file filename, by default check_results.rds
in .GlobalEnv under the name checkdb.
# NOT RUN {### In this first example, we use a small file synchronized with zcrandb.checkdb_load(system.file("aabb", "zcheck_results.rds", package = "RWsearch"))
dim(checkdb)
head(checkdb, 15)
# }