go fmt
go lint
go vet
This fix fixes several `go fmt`, `go lint`, and `go vet` issues, to make goreportcard happy: https://goreportcard.com/report/github.com/miekg/coredns Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Adds a middleware to enable tracing with OpenTracing/OpenZipkin. Enabling tracing will have a large impact on performance so it is not advisable in production.