net/http: fix ordering & data race in TestTransportEventTrace_h2
Ordering fix: this CL swaps the order of the log write and the channel close
in WroteRequest. I could reproduce the bug by putting a sleep between the two
when the channel close was first. It needs to happen after the log.
Data race: use the log buffer's mutex when reading too. Not really
important once the ordering fix above is fixed (since nobody is
concurrently writing anymore), but for consistency.
Fixes #16414
Change-Id: If6657884e67be90b4455c8f5a6f7bc6981999ee4
Reviewed-on: https://go-review.googlesource.com/28078
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>