This is a reduced test case to help with Go issue #27415.
By running the benchmarks 10 times:
go test -bench=. -count=10 .
And comparing go versions:
go version go1.11 darwin/amd64
go version devel +be10ad7622 Wed Aug 22 22:26:40 2018 +0000 darwin/amd64
I observed the following with benchstat:
name old time/op new time/op delta
BboltWrites-4 281µs ± 1% 8283µs ±11% +2843.16% (p=0.000 n=8+10)