Migrate to cargo_embargo. am: 59f8e81ad2

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/async-stream-impl/+/2824655

Change-Id: If0791a5fd938ae5a7100cc2bce1da37e09e926dc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>