Merge "Mark apex-available" into main am: 486185f6b1

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/futures-util/+/3164204

Change-Id: I31118a8c1ff82eb9af2334fe2582626ad47713cc
Signed-off-by: Automerger Merge Worker <[email protected]>