How to register custom structured streaming source

[Farshid Zavareh]

Hello.

I need to create a custom streaming source by extending *FileStreamSource*.
The idea is to override *commit*, so that processed files (S3 objects in my
case) are renamed to have a certain prefix. However, I don't know how to
use this custom source. Obviously I don't want to compile Spark -- the
application will be running on Amazon EMR clusters.

Thanks,
Farshid