A reference to an asynchronous deferred task submitted to the Ramp API (e.g. card issuance, user creation, limit creation).
Pass ref.id to Ramp.Poller.poll/3 to block until the task completes,
or poll it manually via Ramp.Poller.status/2.
Summary
Types
@type t() :: %Ramp.DeferredTaskRef{id: String.t()}