func GetCPUTime() int64 {
	var ts unix.Timespec
	if err := unix.ClockGettime(unix.CLOCK_PROCESS_CPUTIME_ID, &ts); err != nil {
		grpclog.Fatal(err)
	}
	return ts.Nano()
}
GetCPUTime returns the how much CPU time has passed since the start of this process.
package syscall
import (
	"fmt"
	"net"
	"syscall"
	"time"
	"golang.org/x/sys/unix"
	"google.golang.org/grpc/grpclog"
)