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 `--ttl` flag to allow users to set the IPv4 TTL or IPv6 hop limit, providing control over packet lifespan and helping diagnose network topology issues.
Apply the negotiated DSCP value to the UDP socket after a successful session open and clear it before closing to support network-level quality of service. This change adds platform-specific socket option handling for IPv4 TOS and IPv6 Traffic Class.
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.