Migrate to cargo_embargo. am: a8ceee78cb am: 983bdbe2b1

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/async-stream/+/2797799

Change-Id: I35d01cfe92c6f520d21435ae60c6119df9b82a26
Signed-off-by: Automerger Merge Worker <[email protected]>