private boolean isAnyNodeConnecting() {
        for (Node node : metadataUpdater.fetchNodes()) {
            if (connectionStates.isConnecting(node.idString())) {
                return true;
            }
        }
        return false;
    }
Return true if there's at least one connection establishment is currently underway
clients/src/main/java/org/apache/kafka/clients/NetworkClient.java