Where data is buffered before sending to output modules

Where data is buffered before sending to output modules

Hello,

We have a basic flow which contains; OPC UA as input module and Kafka producer as output module. Between these two components we have some basic tranformations with timestamp, split and property mapper modules.

We lost the Kafka due to some system errors. When we avoid the issues and get Kafka up & running again, Crosser started to sending data from the last point before Kafka was down.  And it still continues to sending old messages.

To be able to monitor those buffer (How many messages are there in the buffer and how many of them are sent), we would like to investigate the buffer mechanism. Where can we get the detailed documentation about this situation and buffering in Crosser?