Small async improvements

Author: dnperfors

src/TestableHttpClient/HttpRequestMessageExtensions.cs

@@ -114,7 +114,10 @@ internal static bool HasContent(this HttpRequestMessage httpRequestMessage, stri
             return false;
         }
 
-        var stringContent = httpRequestMessage.Content.ReadAsStringAsync().Result;
+        var stringContent = httpRequestMessage.Content.ReadAsStringAsync()
+            .ConfigureAwait(false)
+            .GetAwaiter()
+            .GetResult();
 
         return pattern switch
         {

src/TestableHttpClient/Response/TimeoutResponse.cs

@@ -10,9 +10,9 @@ public async Task ExecuteAsync(HttpResponseContext context, CancellationToken ca
         {
 #if NETSTANDARD
             cancelationSource.Cancel(false);
-            await Task.FromCanceled<HttpResponseMessage>(cancellationToken).ConfigureAwait(true);
+            await Task.FromCanceled<HttpResponseMessage>(cancellationToken).ConfigureAwait(false);
 #else
-            await cancelationSource.CancelAsync().ConfigureAwait(true);
+            await cancelationSource.CancelAsync().ConfigureAwait(false);
 #endif
         }