Update the documentation for scatter to include streams parameter. (#42814)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/41827
Current:
https://pytorch.org/docs/stable/cuda.html#communication-collectives
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42814
Reviewed By: smessmer
Differential Revision: D23033544
Pulled By: mrshenli
fbshipit-source-id: 88747fbb06e88ef9630c042ea9af07dafd422296
