code: func getStackTracer(err error) (stackTracer, bool) {
  	var st stackTracer
  
  	ForEachCause(err, func(err error) bool {
  		if s, ok := err.(stackTracer); ok {
  			st = s
  
  			return false
  		}
  
  		return true
  	})
  
  	return st, st != nil
  }
docs: // getStackTracer returns the stack trace from an error (if any).