public Collection<ConnectorTaskId> taskIdsToRestart() {
        return idsToRestart;
    }
Get the immutable collection of {@link ConnectorTaskId} for all tasks to be restarted
based upon the {@link #restartRequest() restart request}.

@return the IDs of the tasks to be restarted; never null but possibly empty
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/RestartPlan.java