static async System.Threading.Tasks.Task Main(string[] args) { SampleServiceClient client = new SampleServiceClient(); using (new OperationContextScope(client.InnerChannel)) { // We will use a custom class called UserInfo to be passed in as a MessageHeader string bearerToken = "Bearer 23y7289387893728938792309023092"; // Add a SOAP Header to an outgoing request MessageHeader aMessageHeader = MessageHeader.CreateHeader("Authorization", "http://tempuri.org", bearerToken); OperationContext.Current.OutgoingMessageHeaders.Add(aMessageHeader); // Add a HTTP Header to an outgoing request HttpRequestMessageProperty requestMessage = new HttpRequestMessageProperty(); requestMessage.Headers["Authorization"] = "Bearer 23y7289387893728938792309023092"; OperationContext.Current.OutgoingMessageProperties[HttpRequestMessageProperty.Name] = requestMessage; var result = await client.PingAsync("Hello"); } }