Preroller: Make sure writer still exists before writing
Preroller: Make sure writer still exists before writing

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