public Long reauthenticationLatencyMs() {
        return authenticator.reauthenticationLatencyMs();
    }
Return the number of milliseconds that elapsed while re-authenticating this
session from the perspective of this instance, if applicable, otherwise null.
The server-side perspective will yield a lower value than the client-side
perspective of the same re-authentication because the client-side observes an
additional network round-trip.

@return the number of milliseconds that elapsed while re-authenticating this
        session from the perspective of this instance, if applicable,
        otherwise null
clients/src/main/java/org/apache/kafka/common/network/KafkaChannel.java