internal async Task RejectAsync()

in src/Microsoft.Azure.Relay/RelayedHttpListenerContext.cs [85:128]
39 lines of code
7 McCabe index (conditional complexity)

        internal async Task RejectAsync(Uri rendezvousUri)
        {
            IClientWebSocket clientWebSocket = null;
            try
            {
                if (this.Response.StatusCode == HttpStatusCode.Continue)
                {
                    this.Response.StatusCode = HttpStatusCode.BadRequest;
                    this.Response.StatusDescription = "Rejected by user code";
                }

                // Add the status code/description to the URI query string
                int requiredCapacity = rendezvousUri.OriginalString.Length + 50 + this.Response.StatusDescription.Length;
                var stringBuilder = new StringBuilder(rendezvousUri.OriginalString, requiredCapacity);
                stringBuilder.AppendFormat("&{0}={1}", HybridConnectionConstants.StatusCode, (int)this.Response.StatusCode);
                stringBuilder.AppendFormat("&{0}={1}", HybridConnectionConstants.StatusDescription, WebUtility.UrlEncode(this.Response.StatusDescription));
                Uri rejectUri = new Uri(stringBuilder.ToString());

                clientWebSocket = this.CreateWebSocket();
                using (var cancelSource = new CancellationTokenSource(AcceptTimeout))
                {
                    await clientWebSocket.ConnectAsync(rejectUri, cancelSource.Token).ConfigureAwait(false);
                }
            }
            catch (Exception e) when (!Fx.IsFatal(e))
            {
                WebException webException;
                HttpWebResponse httpWebResponse;
                if (e is WebSocketException &&
                    (webException = e.InnerException as WebException) != null &&
                    (httpWebResponse = webException.Response as HttpWebResponse) != null && 
                    httpWebResponse.StatusCode == HttpStatusCode.Gone)
                {
                    // status code of "Gone" is expected when rejecting a client request
                    return;
                }

                RelayEventSource.Log.HandledExceptionAsWarning(this, e);
            }
            finally
            {
                clientWebSocket?.WebSocket?.Abort();
            }
        }