Function describe_quorum 

pub fn describe_quorum(
    request: &DescribeQuorumRequest,
    quorum: &QuorumStateSnapshot,
) -> DescribeQuorumResponse

Answers a decoded DescribeQuorum request from quorum, this node’s consensus snapshot.

Shared between the controller listener (this module’s own caller, kip853::describe_quorum_response) and the broker listener, which forwards to the active controller and answers with this same builder once it holds the leader’s own snapshot (crates/broker/src/handlers/ describe_quorum.rs) – one implementation on both listeners (#814, #1034).