LMDB backend @api public
@param [Hash] options @option options [String] :dir Environment directory @option options [::LMDB::Environment] :backend Use existing backend instance @option options [String or nil] :db Database name
(see Proxy#clear)
(see Proxy#close)
(see Defaults#create)
(see Proxy#delete)
(see Proxy#increment)
(see Proxy#key?)
(see Proxy#load)
(see Proxy#store)
[Validate]