in src/Microsoft.Azure.WebJobs.Extensions.Kafka/Output/KafkaProducer.cs [149:163]
private static string FindTopic(string topic, IKafkaEventData actualItem)
{
var topicUsed = topic;
if (string.IsNullOrEmpty(topic))
{
topicUsed = actualItem.Topic;
if (string.IsNullOrEmpty(topicUsed))
{
throw new ArgumentException("No topic was defined in Kafka attribute or in KafkaEventData");
}
}
return topicUsed;
}