internal/trace: fix recorder.Write return value for header-only buffers
Fix issue #77083
Change-Id: I9189d1e3a6efea8478224164e820f50c818abcd5
GitHub-Last-Rev:
bb24cbda95f0b5b10aeae9a5ee8cbe215ba6d4eb
GitHub-Pull-Request: golang/go#77092
Reviewed-on: https://go-review.googlesource.com/c/go/+/734300
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Commit-Queue: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>