with type +'a io = 'a Lwt.t
and type key = string
and type value = string
and type period = int64
type +'a io = 'a Lwt.t
The type of a blocking computation that will produce a value of type
default_period t returns default period after which session keys will expire. Depending on the backend, this value may vary over time.
generate ?expiry ?value t will allocate a new session in the backend
t and return its associated
key. The session will expire
expiry seconds from now, defaulting to
default_period t if one is not explicitly specified.
The key should be unique, though it may not be in order to allow implementations that use randomness or hashing to conform to this interface.
clear t key removes
key from the backend
t. The backend may choose to persist the session value beyond this call. If it does any subsequent operations involving
key behave as if it was not there.
get t key returns the session value, if present and unexpired, together with its expiry period as of now.