tests/source_file: Speedups via chunk_duration
tests/source_file: Speedups via chunk_duration

cdgraff/StreamMachine,pteich/StreamMachine,SCPR/StreamMachine,cdgraff/StreamMachine,StreamMachine/StreamMachine,pedropapa/StreamMachine,pedropapa/StreamMachine,DreamNetwork/StreamMachine,StreamMachine/StreamMachine,DreamNetwork/StreamMachine,SCPR/StreamMachine,pteich/StreamMachine