atm - Make sure sync method of access token handler is not invoked

Author: Erwinvandervalk

access-token-management/src/AccessTokenManagement/AccessTokenHandler.cs

@@ -40,6 +40,13 @@ public AccessTokenHandler(
     /// <returns></returns>
     protected abstract Task<ClientCredentialsToken> GetAccessTokenAsync(bool forceRenewal, CancellationToken cancellationToken);
 
+    /// <inheritdoc/>
+    protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken)
+    {
+        throw new NotSupportedException(
+            "The (synchronous) Send() method is not supported. Please use the async SendAsync variant. ");
+    }
+
     /// <inheritdoc/>
     protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
     {