code: func NewOrderedSetWithCapacity(capacity int) *OrderedSet {
  	return &OrderedSet{
  		s: make([]string, 0, capacity),
  		m: make(map[string]int, capacity),
  	}
  }
docs: // NewOrderedSetWithCapacity creates a new ordered set with no values. The
  // returned ordered set can be appended to "capacity" number of times before it
  // grows internally.