turn on go pprof with a compiler flag/tag

pprof.go

// +build pprof

// run `GODEBUG=gctrace=1,scavtrace=1 go test -bench=.* -benchmem -benchtime=1m -tags pprof` to prof benchmarks
package packagename

import (
	"fmt"
	"net/http"
	_ "net/http/pprof"
	"runtime"
	"time"
)

func init() {
	go http.ListenAndServe("localhost:8080", nil)
	go func() {
		for {
			time.Sleep(time.Second)
			runtime.GC()
			fmt.Println(time.Now())
		}
	}()
}