Merge "Make libfutures_io available to DnsResolver" am: 03792089f9 am: d794d89f2a

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/futures-io/+/1742082

Change-Id: Ifdbba3dceadca2094e21e8650633bc28e340ebb2