Where does the value of BasePipelineFactory has been used?

I can see that all the handlers has been added to the Channelpipeline and each handlers processes Specific tasks. Also I can see that MainEventHandler is responsible for all the events but BasePipelineFactory isn't called in MainEvent. Could you please let me know the where the values from Basepipeline is been used? Thanks in advance.

I would recommend you to read Netty documentation to understand how it works.