read = syrupReader => {
    const label = syrupReader.readSelectorAsString();
    if (label !== expectedLabel) {
      throw Error(`Expected label ${expectedLabel}, got ${label}`);
    }
    const value = syrupReader.readBytestring();
    return value;
  }
@param {import('../syrup/decode.js').SyrupReader} syrupReader
@returns {Uint8Array}