@Override
    public String toString() {
        var diffs = new ArrayList<String>();
        addIfDiffers(redundancyDiff, "redundancy", diffs);
        addIfDiffers(searchableCopiesDiff, "searchable-copies", diffs);
        addIfDiffers(groupCountDiff, "groups", diffs);
        for (var kv : groupDiffs.entrySet()) {
            addGroupDiffStringIfDiffers(kv, diffs);
        }
        return String.join(", ", diffs);
    }
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