private static void addIfDiffers(IntegerDiff diff, String name, List<String> diffs) {
        if (diff.differs()) {
            diffs.add("%s: %d -> %d".formatted(name, diff.before, diff.after));
        }
    }
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