Use internal monotonic time by default and introduce poll_timeouts_at for callers requiring a specific sampled Instant. This simplifies the API for standard usage while maintaining flexibility for external event loops.
Introduce a BackendPeer abstraction to transparently switch between fake and real IRTT backends. This simplifies test logic by removing manual skip checks and providing a consistent interface for server lifecycle management.
Introduce a mechanism to run tests against a live irtt binary to verify real-world protocol interoperability, including HMAC authentication and various timestamp modes.