private static <T> void assertNoDuplicates(List<T> collection, String assertionMessage) {
        assertEquals(new HashSet<>(collection).size(), collection.size(), assertionMessage);
    }
Ensure that no connectors or tasks that were already assigned during the previous round are newly assigned in this round,
and that each newly-assigned connector and task is only assigned to a single worker.
connect/runtime/src/test/java/org/apache/kafka/connect/runtime/distributed/IncrementalCooperativeAssignorTest.java