code: function opt (option) {
    return function (value) {
      if (typeof value === 'undefined') {
        return nn.Getopt(this.binding, nn.NN_SOL_SOCKET, sol[option]);
      }
  
      if(nn.Setopt(this.binding, nn.NN_SOL_SOCKET, sol[option], value) > -1) {
        return true;
      }
  
      throw new Error(nn.Err() + ': ' + this.type + option + '@' + value + '\n');
    }
  }
docs: /* sockopt API workhorse