neon_db_dir: Default directory for persistent NEON database
Description
Use neon_db_dir() to view or access the currently active database
directory. By default, this uses the appropriate application directory
for your operating system, see tools::R_user_dir().
This location can be overridden by setting
the environmental variable NEONSTORE_DB.
# NOT RUN {neon_db_dir()
## Override with an environmental variable:Sys.setenv(NEONSTORE_DB = tempdir())
neon_db_dir()
## UnsetSys.unsetenv("NEONSTORE_DB")
# }