Major Description
We saw a cluster in the wild where some negotiation steps between endpoints were additionally delayed for some small number of seconds. The existing --rpc_negotiation_timeout_ms gflag can help workaround this on servers, but there's no equivalent in clients, whose negotiation timeouts are hardcoded to 3s in the C++ client and 10s in the Java client.
It would be nice to expose a simple API to reconfigure the negotiation timeout.