NSG Flow Logs Dashboard - Logstash input config error

[digitalbydesign]

I've been able to get the dashboard for Azure NSG Flow logs setup and it's quite amazing. The only issue I'm having is that I've been unable to resolve is within the logstash azure_event_hubs input config. Setting the maxBatchSize>=1000 seems to throw errors within logstash sending the following error: maxBatchSize (1000) needs to be lower than the prefetchCount (300). I can't seem to figure out how to change the prefetchCount. Any help would be appreciated.