func StopNow(e error, msg string, exitcode int) {
	if e == nil {
		return
	}
	fmt.Fprintf(os.Stderr, "%s: %s\n", msg, e)
	log.Printf("%s: '%s'\n", msg, e)
	os.Exit(exitcode)
}
StopNow errors and exit.
package errs
import (
	"fmt"
	"log"
	"os"
)
func New(msg interface{}) error {
	return &basicError{msg}
}
type basicError struct {
	msg interface{}
}
func (e *basicError) Error() string {
	return fmt.Sprintf("%v", e.msg)
}