code: func (h Headers) ContainsKV(k string, v string) bool {
  	for i := 0; i < len(h); i += 2 {
  		if h[i] == k && h[i+1] == v {
  			return true
  		}
  	}
  	return false
  }
docs: /*
  	ContainsKV returns true if a set of Headers contains a key and value pair.
  */