private static void appendIntsAsSet(StringBuilder sb, String setName, List<Integer> ints) {
        sb.append(setName).append(" {");
        sb.append(ints.stream().map(i -> Integer.toString(i)).collect(Collectors.joining(", ")));
        sb.append('}');
    }
Immutable representation of the high-level difference between two distribution configs.

<code>toString()</code> gives a human-readable summary of the diff.

See <code>DistributionDiffCalculatorTest</code> for examples of diff output.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/DistributionDiff.java