public override async Task WriteAsync()

in src/Microsoft.Azure.Relay/HybridHttpConnection.cs [423:465]
37 lines of code
6 McCabe index (conditional complexity)

            public override async Task WriteAsync(byte[] array, int offset, int count, CancellationToken cancelToken)
            {
                RelayEventSource.Log.HybridHttpResponseStreamWrite(this.TrackingContext, count);
                this.context.Response.SetReadOnly();
                using (var timeoutCancelSource = new CancellationTokenSource(this.WriteTimeout))
                using (var linkedCancelSource = CancellationTokenSource.CreateLinkedTokenSource(cancelToken, timeoutCancelSource.Token))
                using (await this.asyncLock.LockAsync(linkedCancelSource.Token).ConfigureAwait(false))
                {
                    if (!this.responseCommandSent)
                    {
                        FlushReason flushReason;
                        if (this.connection.rendezvousWebSocket != null)
                        {
                            flushReason = FlushReason.RendezvousExists;
                        }
                        else
                        {
                            int bufferedCount = this.writeBufferStream != null ? (int)this.writeBufferStream.Length : 0;
                            if (count + bufferedCount <= MaxControlConnectionBodySize)
                            {
                                // There's still a chance we might be able to respond over the control connection, accumulate bytes
                                if (this.writeBufferStream == null)
                                {
                                    int initialStreamSize = Math.Min(count * 2, MaxControlConnectionBodySize);
                                    this.writeBufferStream = new MemoryStream(initialStreamSize);
                                    this.writeBufferFlushTimer = new Timer((s) => ((ResponseStream)s).OnWriteBufferFlushTimer(), this, WriteBufferFlushTimeout, Timeout.InfiniteTimeSpan);
                                }

                                this.writeBufferStream.Write(array, offset, count);
                                return;
                            }

                            flushReason = FlushReason.BufferFull;
                        }

                        // FlushCoreAsync will rendezvous, send the responseCommand, and any writeBufferStream bytes
                        await this.FlushCoreAsync(flushReason, linkedCancelSource.Token).ConfigureAwait(false);
                    }

                    var buffer = new ArraySegment<byte>(array, offset, count);
                    await this.connection.SendBytesOverRendezvousAsync(buffer, WebSocketMessageType.Binary, false, linkedCancelSource.Token).ConfigureAwait(false);
                }
            }