eg
```
"impacts": [
            {
              "severity": 3,
              "description": "Searches might return slower than usual. Fewer redundant copies of the data exist on 2 indices [.ds-logslogslogs-2022.03.29-000001, my-index-000001].",
              "impact_areas": [ "search" ]
            }
          ]
```
server/src/test/java/org/elasticsearch/health/HealthIndicatorServiceTests.java
/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0 and the Server Side Public License, v 1; you may not use this file except
 * in compliance with, at your election, the Elastic License 2.0 or the Server
 * Side Public License, v 1.
 */
package org.elasticsearch.health;
import org.elasticsearch.test.ESTestCase;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class HealthIndicatorServiceTests extends ESTestCase {
    public void testImpactsOrderAndLimit() {
        
        HealthIndicatorService service = getTestHealthIndicatorService();
        HealthStatus status = randomFrom(HealthStatus.RED, HealthStatus.YELLOW, HealthStatus.GREEN);
        Set<HealthIndicatorImpact> impacts = new HashSet<>();
        for (int i = 0; i < 10; i++) {
            impacts.add(new HealthIndicatorImpact(randomIntBetween(5, 20), randomAlphaOfLength(20)));
        }
        HealthIndicatorImpact impact1 = new HealthIndicatorImpact(1, randomAlphaOfLength(20));
        HealthIndicatorImpact impact2 = new HealthIndicatorImpact(2, randomAlphaOfLength(20));
        HealthIndicatorImpact impact3 = new HealthIndicatorImpact(3, randomAlphaOfLength(20));