private Map<String, Collection<Integer>> revokedAsMap() {
        if (revokedConnectorIds == null && revokedTaskIds == null) {
            return null;
        }
        // Using LinkedHashMap preserves the ordering, which is helpful for tests and debugging
        Map<String, Collection<Integer>> taskMap = new LinkedHashMap<>();
        Optional.ofNullable(revokedConnectorIds)
                .orElseGet(Collections::emptyList)
                .stream()
                .distinct()
                .forEachOrdered(connectorId -> {
                    Collection<Integer> connectorTasks =
                            taskMap.computeIfAbsent(connectorId, v -> new ArrayList<>());
                    connectorTasks.add(CONNECTOR_TASK);
                });

        Optional.ofNullable(revokedTaskIds)
                .orElseGet(Collections::emptyList)
                .forEach(taskId -> {
                    String connectorId = taskId.connector();
                    Collection<Integer> connectorTasks =
                            taskMap.computeIfAbsent(connectorId, v -> new ArrayList<>());
                    connectorTasks.add(taskId.task());
                });
        return taskMap;
    }
Return an empty assignment.

@return an empty assignment
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/distributed/ExtendedAssignment.java