When you call an asynchronous method with an await, the method you're calling from must also be asynchronous. But, sometimes that's problematic: Perhaps you're working with existing code, or you're implementing code in a context where it's difficult to make it asynchronous.

You can “localize” the management of asynchronous calls using Task.Run(). In the following code, look at the two instances of Task.Run(), Wait(), and Result to see how to do it:

using (HttpContent content = new StringContent(text, Encoding.UTF8, "text/xml"))
using (HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, url))
{
    request.Headers.Add("SOAPAction", "");
    request.Content = content;
    var task1 = Task.Run(() => httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead));
    task1.Wait();
    var response = task1.Result;
 
    var task2 = Task.Run(() => response.Content.ReadAsStreamAsync());
    task2.Wait();
    var stream = task2.Result;
 
    using var reader = new StreamReader(stream);
    return reader.ReadToEnd();
}