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/main/java/org/elasticsearch/cluster/routing/allocation/ShardsAvailabilityHealthIndicatorService.java
).flatMap(Function.identity()).collect(joining(", "))
                ).append(".");
            } else {
                builder.append("all shards available.");
            }
            return builder.toString();
        }
        private static Stream<String> createMessage(int count, String singular, String plural) {
            return switch (count) {
                case 0 -> Stream.empty();
                case 1 -> Stream.of("1 " + singular);
                default -> Stream.of(count + " " + plural);
            };
        }
        public HealthIndicatorDetails getDetails(boolean includeDetails) {
            if (includeDetails) {
                return new SimpleHealthIndicatorDetails(
                    Map.of(
                        "unassigned_primaries",
                        primaries.unassigned,
                        "initializing_primaries",
                        primaries.initializing,
                        "creating_primaries",
                        primaries.unassigned_new,
                        "restarting_primaries",
                        primaries.unassigned_restarting,
                        "started_primaries",
                        primaries.started + primaries.relocating,
                        "unassigned_replicas",
                        replicas.unassigned,