Backpressure

1. The Pattern

When a producer outruns its consumer, something, somewhere, must give: a buffer fills, data drops, or the producer slows. Backpressure is choosing which and where on purpose, and propagating the consumer's "slow down" signal upstream. The alternative is letting the default choice, an unbounded buffer, make itself later, as an outage.

You have met this pattern three times already. The bidirectional lesson's slow phone filled a gateway's memory