### Description

The health API response can become a few MBs (2-3MB if 50K indices are affected).

In less extreme situations the response can be in the 10s/100s of KB. 

It might be worthwhile looking into chunking its response (this might provide clients with a better experience too)
server/src/main/java/org/elasticsearch/health/Diagnosis.java
public static final String ID_FIELD = "id";
        public static final String NAME_FIELD = "name";
        public enum Type {
            INDEX("indices"),
            NODE("nodes"),
            SLM_POLICY("slm_policies"),
            SNAPSHOT_REPOSITORY("snapshot_repositories");
            private final String displayValue;
            Type(String displayValue) {
                this.displayValue = displayValue;
            }
        }