protected synchronized boolean ensureCoordinatorReady(final Timer timer) {
        return ensureCoordinatorReady(timer, false);
    }
Ensure that the coordinator is ready to receive requests.

@param timer Timer bounding how long this method can block
@return true If coordinator discovery and initial connection succeeded, false otherwise
clients/src/main/java/org/apache/kafka/clients/consumer/internals/AbstractCoordinator.java