KIP-764 — Configurable backlog size for creating Acceptor

Accepted Kafka 3.2 Broker

Adds a configurable connection-acceptance rate limit to the Kafka broker's `Acceptor` so that a burst of new TCP connections (e.g. after a preferred-leader election) does not fill the SYN backlog and drop subsequent connection attempts. Under high partition counts a rolling restart or leader election causes hundreds of clients to reconnect simultaneously, overwhelming the kernel TCP backlog.

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