User Payments to Participants in a Delegated Hydra

[Pdest08]

Why

Hydra heads require liveness from all participants to progress. Not all users can guarantee that ability or want to do so (ex. Someone wants to interact a couple times in a head rather than the full life cycle.) A user can delegate the snapshotting to a participant in the head via an API. We may want to incentivize participants to offer this service to end users in certain scenarios.

What

In a delegated topology, a user delegates their snapshot keys to a participant in a head, while keeping control of their signing keys. A participant may want to charge a fee for providing this delegation service to users (a participant has to remain online while users can come and go).

How

I'll leave this section to input from the working group but sort of API is needed as well as some sort of accounting system to track fees to participants.