KafkaAvroAsyncSerializer.cs

public class KafkaAvroAsyncSerializer<T> : IAsyncSerializer<T>
{
    private readonly SchemaRegistryAvroObjectSerializer serializer;

    public KafkaAvroAsyncSerializer(string schemaRegistryUrl, TokenCredential credential, string schemaGroup, Boolean autoRegisterSchemas = false)
    {
        this.serializer = new SchemaRegistryAvroObjectSerializer(
            new SchemaRegistryClient(
                schemaRegistryUrl,
                credential),
            schemaGroup,
            new SchemaRegistryAvroObjectSerializerOptions()
            {
                AutoRegisterSchemas = autoRegisterSchemas
            });
    }

    public async Task<byte[]> SerializeAsync(T o, SerializationContext context)
    {
        if (o == null)
        {
            return null;
        }

        using (var stream = new MemoryStream())
        {
            await serializer.SerializeAsync(stream, o, typeof(T), CancellationToken.None);
            return stream.ToArray();
        }
    }
}