code: func decodeSettings(headerVal string) ([]http2.Setting, error) {
  	b, err := base64.RawURLEncoding.DecodeString(headerVal)
  	if err != nil {
  		return nil, err
  	}
  	if len(b)%6 != 0 {
  		return nil, err
  	}
  	settings := make([]http2.Setting, 0)
  	for i := 0; i < len(b)/6; i++ {
  		settings = append(settings, http2.Setting{
  			ID:  http2.SettingID(binary.BigEndian.Uint16(b[i*6 : i*6+2])),
  			Val: binary.BigEndian.Uint32(b[i*6+2 : i*6+6]),
  		})
  	}
  
  	return settings, nil
  }
docs: // decodeSettings decodes the base64url header value of the HTTP2-Settings
  // header. RFC 7540 Section 3.2.1.