private static Set<ApplicationId> toApplicationInstances(HttpResponse<byte[]> response, TenantName tenantName) {
        Set<ApplicationId> applicationIds = new HashSet<>();
        toInspector(response).traverse((ArrayTraverser) (___, entryObject) -> {
            ApplicationName applicationName = ApplicationName.from(entryObject.field("application").asString());
            entryObject.field("instances").traverse((ArrayTraverser) (____, instanceObject) ->
                    applicationIds.add(ApplicationId.from(tenantName,
                                                          applicationName,
                                                          InstanceName.from(instanceObject.field("instance").asString()))));
        });
        return applicationIds;
    }
Returns the "message" element contained in the JSON formatted response.
hosted-api/src/main/java/ai/vespa/hosted/api/ControllerHttpClient.java