public String currentAssignment() {
        return "[activeTasks: (" + assignedActiveTasks.taskIds() +
               ") standbyTasks: (" + assignedStandbyTasks.taskIds() + ")]";
    }
@return the previous tasks assigned to this consumer ordered by lag, filtered for any tasks that don't exist in this assignment
streams/src/main/java/org/apache/kafka/streams/processor/internals/assignment/ClientState.java