This should be slightly more efficient and insulate this code from
changes to the internal representation/alignment of slices and strings.
The interface header lacks an unsafe constructor but is also tweaked
to follow any future alignment changes, if they should occur.
Change-Id: I54a3a93f248d3eef883d5ebf9ed75cc1f5c20977
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/547336
Reviewed-by: Michael Stapelberg <stapelberg@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Run-TryBot: David Chase <drchase@google.com>
Auto-Submit: Michael Stapelberg <stapelberg@google.com>
