public async Task CloseAsync()

in src/Microsoft.Azure.Relay/HybridConnectionListener.cs [341:383]
35 lines of code
4 McCabe index (conditional complexity)

        public async Task CloseAsync(CancellationToken cancellationToken)
        {
            try
            {
                List<HybridConnectionStream> clients;
                lock (this.ThisLock)
                {
                    if (this.closeCalled)
                    {
                        return;
                    }

                    RelayEventSource.Log.ObjectClosing(this);
                    this.closeCalled = true;

                    // If the input queue is empty this completes all pending waiters with null and prevents
                    // any new items being added to the input queue.
                    this.connectionInputQueue.Shutdown();

                    // Close any unaccepted rendezvous.  DequeueAsync won't block since we've called connectionInputQueue.Shutdown().
                    clients = new List<HybridConnectionStream>(this.connectionInputQueue.PendingCount);
                    HybridConnectionStream stream;
                    while ((stream = this.connectionInputQueue.DequeueAsync(cancellationToken).ConfigureAwait(false).GetAwaiter().GetResult()) != null)
                    {
                        clients.Add(stream);
                    }
                }

                await this.controlConnection.CloseAsync(cancellationToken).ConfigureAwait(false);

                clients.ForEach(client => ((WebSocketStream)client).Abort());
                RelayEventSource.Log.ObjectClosed(this);
            }
            catch (Exception e) when (!Fx.IsFatal(e))
            {
                RelayEventSource.Log.ThrowingException(e, this);
                throw;
            }
            finally
            {
                this.connectionInputQueue.Dispose();
            }
        }