storr_environment: Environment object cache driver
In storr: Simple Key Value Stores

Fast but transient environment driver. This driver saves objects in a local R environment, without serialisation. This makes lookup fast but it cannot be saved across sesssions. The environment storr can be made persistent by saving it out as a file storr though.

storr_environment(envir = NULL, hash_algorithm = NULL,
  default_namespace = "objects")

driver_environment(envir = NULL, hash_algorithm = NULL)

`envir`	The environment to point the storr at. The default creates an new empty environment which is generally the right choice. However, if you want multiple environment storrs pointing at the same environment then pass the `envir` argument along.
`hash_algorithm`	Name of the hash algorithm to use. Possible values are "md5", "sha1", and others supported by `digest`. If not given, then we will default to "md5".
`default_namespace`	Default namespace (see `storr`).

# Create an environment and stick some random numbers into it:
st <- storr_environment()
st$set("foo", runif(10))
st$get("foo")

# To make this environment persistent we can save it to disk:
path <- tempfile()
st2 <- st$archive_export(path)
# st2 is now a storr_rds (see ?storr_rds), and will persist across
# sessions.

# or export to a new list:
lis <- st$export(list())
lis