Processor to update the fields with the data

DownloadLoadFields.cs

public class DownloadLoadFields : DownloadIndexableLoadFieldsProcessor
{
    protected override IEnumerable<IIndexableDataField> GetFields(DownloadEventIndexableLoadFieldsPipelineArgs args)
    {
        Assert.ArgumentNotNull(args, nameof(args));

        PageEventData eventData = args.EventData;

        Assert.IsNotNull(eventData, "eventData");

        List<IIndexableDataField> indexableDataFieldList = new List<IIndexableDataField>()
        {
            new IndexableDataField<Guid>("visit.InteractionId", args.InteractionId),
            new IndexableDataField<Guid>("contact.Id", args.ContactId),
            new IndexableDataField<string>("contact.download", args.EventData.ItemId.ToString()),
            new IndexableDataField<string>("type", "assetdownloadevent")
        };

        return indexableDataFieldList;
    }
}