protected void setDlqWriter(DeadLetterQueueWriter writer) {
        this.dlqWriter = writer;
    }
We need to use the original event object to get the fieldName value.
For some reason, getting it from the eventData map of asyncFeed doesn't work

@param event The original event object
@param fieldName The field name to get
@return The value of the field or the field name if it doesn't exist
integration/logstash-plugins/logstash-output-vespa/src/main/java/org/logstashplugins/VespaFeed.java