public InvocationTester(Action<HttpRequestMessage> assert = null, Action<HttpRequestFactory> configure = null, Action<IEnumerable<Parameter>, ParameterTransformContext> pipelineAction = null, ApiSettings settings = null)
 {
     _settings = settings ?? new ApiSettings();
     _assert = assert ?? (a => { });
     _configure = configure ?? (a => { });
     _pipelineAction = pipelineAction ?? ((a, b) => { });
 }