Real-time pacing

Deliver records over wall-clock time, the way a real event source would — for streaming tests and consumer back-pressure experiments:

synth.Rate[Event](synth.RateConfig{PerSecond: 5000, Jitter: 0.2}).
    Run(ctx, func(e Event) error { return myProducer.Send(e) })

Field	Meaning
PerSecond	target delivery rate
Jitter	fraction of that interval to vary by, so arrivals aren't a metronome

Synth paces the handoff; where the events go is your code's decision. The handler is your Kafka producer, your HTTP client, your channel — Synth opens no connection of its own, here or anywhere else.

Cancelling the context stops the run; the handler's error stops it too, and is returned.