CheckModel will check that the Model attribute is correctly set; also return the value.

SessionMiddleware is a convenience middleware for initializing the session state container on the request context.

WithSessions initializes a container for the session states on the context.

ModelNameRegexp defines the names that are accepted in the cosmosmodel:\"\" specifier (`^[a-zA-Z_]+/[0-9]+$`).

Transaction is simply a wrapper around Session which unlocks some of the methods that should only be called inside an idempotent closure.

Client is an interface exposing the public API of the cosmosapi.Client struct.