Exclude System.Runtime.CompilerServices.NullableContextAttribute (#66)

* HttpClient

* .

* .

* .

src-examples/ConsoleAppIHttpClient/Program.cs

@@ -0,0 +1,13 @@
+using System.Net.Http;
+using System.Net.Http.Json;
+
+var httpClient = new HttpClient();
+var httpClientProxy = new HttpClientProxy(httpClient);
+
+var result = await httpClientProxy.GetAsync("https://www.google.nl");
+var todo = await httpClientProxy.GetFromJsonAsync<Todo>("https://jsonplaceholder.typicode.com/todos/1");
+var postResult = await httpClientProxy.PostAsJsonAsync("https://jsonplaceholder.typicode.com/todos", new Todo { Id = 123 });
+var patchResult = await httpClientProxy.PatchAsJsonAsync("https://jsonplaceholder.typicode.com/todos", new Todo { Id = 400 });
+var putResult = await httpClientProxy.PutAsJsonAsync("https://jsonplaceholder.typicode.com/todos", new Todo { Id = 444 });
+
+int x = 0;