Simple .Net producer using Schema Registry

internal class Program
{
    private static int _inFlight;
    private static long _delivered;
 
    private static void HandleDeliveryResult(int msgid, DeliveryResult<string, GenericRecord> deliveryResult)
    {
        if (msgid % 1024 == 0)  // writing to console on every message would be a bottleneck
        {
            Console.WriteLine($"Delivered '{deliveryResult.Value}' to '{deliveryResult.TopicPartitionOffset}', in flight on delivery confirmation: {_inFlight}");
        }
        --_inFlight;
        ++_delivered;
    }
 
    private static void Main(string[] args)
    {
        var schema = (Avro.RecordSchema) Avro.Schema.Parse(@"{
                ""type"": ""record"",
                ""name"": ""ExampleRecord"",
                ""namespace"": ""ExampleSchema"",
                ""fields"": [
                    {
                        ""name"": ""message_id"",
                        ""type"": ""int""
                    },
                    {
                        ""name"": ""in_flight_on_send"",
                        ""type"": ""int""
                    }
                ]
            }");
 
        var schemaRegistryConfig = new SchemaRegistryConfig { Url = "http://schemareg:7788/api/v1" };
        var producerConfig = new ProducerConfig { BootstrapServers = "broker:9092" };
 
        using (var schemaRegistry = new CachedSchemaRegistryClient(schemaRegistryConfig))
        using (var producer = new ProducerBuilder<string, GenericRecord>(producerConfig)
            .SetValueSerializer(new AvroSerializer<GenericRecord>(schemaRegistry, new AvroSerializerConfig
            {
                ProtocolVersion = AvroSerializerConfig.ProtocolVersions.SchemaMetadataIdAsVersionProtocol
            }))
            .Build())
        {
            int msgCounter = 0;
            var start = DateTime.Now;
            while (!(Console.KeyAvailable && Console.ReadKey().Key == ConsoleKey.Q || (DateTime.Now - start).TotalSeconds >= 60))
            {
                int msgid = ++msgCounter;
 
                var record = new GenericRecord(schema);
                record.Add("message_id", msgid);
                record.Add("in_flight_on_send", ++_inFlight);
 
                try
                {
                    producer.ProduceAsync("topic", new Message<string, GenericRecord>
                        {
                            Key = msgid.ToString(),
                            Value = record
                        }
                    ).ContinueWith(task => HandleDeliveryResult(msgid, task.Result));
                }
                catch (ProduceException<string, string> e)
                {
                    Console.WriteLine($"Produce failed: {e.Error.Reason}");
                }
            }
            producer.Flush();
            Console.WriteLine("average throughput: {0:N3} msg/sec", _delivered / (DateTime.Now - start).TotalSeconds);
        }
    }
}