Hmmmmm...
Not sure if its known or not, maybe some developers do. In one beta it just streamed or you could download it. In a later beta it was only download and it would play while downloading. I think they made each option exclusive to each beta to test them in depth. Would not be surprised if it ends up shipping with both in the final version but recent reports have been its still download and play only. WE SHALL SEE come Oct. 14th