private static InstanceInfo toInstanceInfo(HttpResponse<byte[]> response, ApplicationId applicationId) {
        List<ZoneDeployment> zones = new ArrayList<>();
        toInspector(response).field("instances").traverse((ArrayTraverser) (___, entryObject) ->
                zones.add(new ZoneDeployment(ZoneId.from(entryObject.field("environment").asString(),
                                                         entryObject.field("region").asString()),
                                             entryObject.field("url").valid() ? Optional.of(entryObject.field("url").asString()) : Optional.empty())));
        return new InstanceInfo(applicationId, zones);
    }
Returns the "message" element contained in the JSON formatted response.
hosted-api/src/main/java/ai/vespa/hosted/api/ControllerHttpClient.java