public static <K, V> Map<V, K> invertAssignment(Map<K, Collection<V>> assignment) {
        Map<V, K> inverted = new HashMap<>();
        for (Map.Entry<K, Collection<V>> assignmentEntry : assignment.entrySet()) {
            K key = assignmentEntry.getKey();
            for (V value : assignmentEntry.getValue())
                inverted.put(value, key);
        }
        return inverted;
    }
Get the version of the connect protocol that is currently active in the group of workers.

@return the current connect protocol version
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/distributed/WorkerCoordinator.java