How to make requests via C #? WebRequest vs HttpClient

I have a project in .Net Framework 4.6.1, and in my research I concluded that I can use the WebRequest to make requests to other web services via the backend.

Issue:

Consider the following code snippets:

Case 1:

public class MyServiceController : ApiController
{
    public void Post()
    {
        // ...
        using (var httpClient = new HttpClient())
        {
            var result = httpClient.GetAsync("https://pt.stackoverflow.com");
        }
        // ...
    }
}

Case 2:

public class MyServiceController : ApiController
{
    public void Post()
    {
        // ...

        var request = WebRequest.Create("https://pt.stackoverflow.com");
        request.Method = "GET";
        // ...

        using (var response = request.GetResponse())
        {
            // ...
        }
    }
}

  

1. If both can help me make a request in C #, what would be the   difference between them? What are the best scenarios?

     

2. Both have support for any HTTP verb?

     

3. Both have support for using the SSL / TLS protocol?

     

4. Which is more performative?

     

5.

Some of them are obsolete and can give me security risks in the request?