code: func (s *dumpState) visitPointerAndCheckIfItIsTheFirstTime(ptr uintptr) bool {
  	for _, addr := range s.visitedPointers {
  		if addr == ptr {
  			return false
  		}
  	}
  	s.visitedPointers = append(s.visitedPointers, ptr)
  	return true
  }
docs: // call to signal that the pointer is being visited, returns true if this is the
  // first visit to that pointer. Used to detect when to output the entire contents
  // behind a pointer (the first time), and when to just emit a name (all other times)