public TopicsSpec immutableCopy() {
        HashMap<String, PartitionsSpec> mapCopy = new HashMap<>();
        mapCopy.putAll(map);
        return new TopicsSpec(Collections.unmodifiableMap(mapCopy));
    }
TopicsSpec maps topic names to descriptions of the partitions in them.

In JSON form, this is serialized as a map whose keys are topic names,
and whose entries are partition descriptions.
Keys may also refer to multiple partitions.  For example, this specification
refers to 3 topics foo1, foo2, and foo3:

{
  "foo[1-3]" : {
     "numPartitions": 3
     "replicationFactor": 3
   }
}
trogdor/src/main/java/org/apache/kafka/trogdor/workload/TopicsSpec.java