Feature: Automatic sessionId

[FredrikOseberg]

Describe the feature request

In Unleash, the rollout strategies are based on a murmur hash. Values that you send in are normalized between 0-100 and used to define if you fall within or without the gradual rollout percentage. In order to make sure that users get the same experience every time, we make sure to attempt to use the same values every time. By default in Unleash, the stickiness is looking for the following values in your context field in prioritised order: userId, sessionId. If we can't find any of these values in the context we will default to a random value and the stickiness will not be guaranteed.

What we've discovered is that most client side applications want the user experience to be consistent, so in the javascript SDK we've implemented a default sessionId property that is set if the user does not provide one. This is also saved to local storage and retrieved on subsequent visits.

We'd like to implement the same in the Swift SDK, leveraging a storage mechanism to store/retreive this value locally to ensure a consistent experience.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.