private static bool IsFatal()

in dotnet/src/Azure.Iot.Operations.Mqtt/Session/MqttSessionClient.cs [800:859]
47 lines of code
26 McCabe index (conditional complexity)

        private static bool IsFatal(Exception e, bool userCancellationRequested = false)
        {
            if (e is MqttConnectingFailedException)
            {
                MqttClientConnectResultCode code = ((MqttConnectingFailedException)e).ResultCode;

                switch (code)
                {
                    case MqttClientConnectResultCode.MalformedPacket:
                    case MqttClientConnectResultCode.ProtocolError:
                    case MqttClientConnectResultCode.UnsupportedProtocolVersion:
                    case MqttClientConnectResultCode.ClientIdentifierNotValid:
                    case MqttClientConnectResultCode.BadUserNameOrPassword:
                    case MqttClientConnectResultCode.Banned:
                    case MqttClientConnectResultCode.BadAuthenticationMethod:
                    case MqttClientConnectResultCode.TopicNameInvalid:
                    case MqttClientConnectResultCode.PacketTooLarge:
                    case MqttClientConnectResultCode.PayloadFormatInvalid:
                    case MqttClientConnectResultCode.RetainNotSupported:
                    case MqttClientConnectResultCode.QoSNotSupported:
                    case MqttClientConnectResultCode.ServerMoved:
                    case MqttClientConnectResultCode.ImplementationSpecificError:
                    case MqttClientConnectResultCode.UseAnotherServer:
                    case MqttClientConnectResultCode.NotAuthorized:
                        return true;
                }
            }

            if (e is SocketException)
            {
                //TODO there is room for a lot more nuance here. Some socket exceptions are more retryable than others so it may
                // be inappropriate to label them all as fatal.
                return true;
            }

            if (e is MQTTnet.Exceptions.MqttProtocolViolationException)
            {
                return true;
            }

            if (e is ArgumentException
                || e is ArgumentNullException
                || e is NotSupportedException)
            {
                return true;
            }

            // MQTTnet may throw an OperationCanceledException/TaskCanceledException even if
            // neither the user nor the session client provides a cancellation token. Because
            // of that, this exception is only fatal if the cancellation token this layer
            // is aware of actually requested cancellation. Other cases signify that MQTTnet
            // gave up on the operation, but the user still wants to retry.
            if ((e is OperationCanceledException || e is TaskCanceledException)
                && userCancellationRequested)
            {
                return true;
            }

            return false;
        }