Optional. Policy for how the results from multiple health checks for
the same endpoint are aggregated. Defaults to NO_AGGREGATION if
unspecified. - NO_AGGREGATION. An EndpointHealth message is returned
for each pair in the health check service. - AND. If any health
check of an endpoint reports UNHEALTHY, then UNHEALTHY is the
HealthState of the endpoint. If all health checks report HEALTHY,
the HealthState of the endpoint is HEALTHY. .