Implementing SignalR

Let’s briefly recap how our healthcheck.client and HealthCheck.Server projects currently work:

1. The healthcheck.client Angular app features a component—the HealthCheckComponent—that, right after being loaded, performs a call to the server-side /health endpoint.
2. The above endpoint is handled by the HealthCheckMiddleware: when called, the HealthCheck.Server ASP.NET Core Web API is configured to launch various ICMP health checks, each one configured to ping a hostname or IP address and return its status (healthy or unhealthy).
3. The health checks’ statuses are wrapped together by the HealthCheckMiddleware and sent in a single JSON response.
4. The Angular app fetches the JSON response and uses it to create an HTML table, thus showing the result in a readable format.

As we can see, the only interaction between the two projects is a single HTTP call issued to the /health endpoint: right after the first health...