How to pass application data by using Messaging SDK for Android/iOS?

Currently, we're using a classic MobileSDK to let users to open tickets from our App. We'd like to switch to Messaging SDK (Android and iOS) in order to have a Bot based on a navigation tree. A value-added vs non-messaging SDK is that we can define or update the navigation tree by using the flow builder, so that a new ticket is only created for specific branches..

That said, we're facing a huge problem: How can we pass application data from the app to the newly created ticket? With application data I mean internal data (eg. log, app version, etc.) that cannot be manually passed by the end user while Bot is in process of transferring to the Agent.

In other words:

1. User starts a new messaging conversation from the top of Bot navigation tree
2. At some point, user navigates to one branch to transfer to Agent
3. With the flow builder we have specified some of the Custom Fields that can be manually provided by the User
4. However, we need to provide additional custom fields in a transparent way (User should not be directly involved..)
5. Once the Ticket is created, we expect ALL custom fields being ready in the ticket, both (3) and (4).

How to implement this by using Messaging SDK for Android/iOS?