title: Flutter httpOnly cookie based authentication
body: <p>I am using flutter_graphql and they have good documentation on how to handle AuthLink but it doesn't fit all kinds of authentication methods.<br />
  for example when using an api which store httpPnly cookie, the cookie does not get stored and even not being send back with every request
  in apollo it would've been solved like that:</p>
  
  <pre><code>const link = createHttpLink({
    uri: '/graphql',
    credentials: 'include'
  });
  
  const client = new ApolloClient({
    cache: new InMemoryCache(),
    link,
  });
  </code></pre>
  
  <p><br />
  but I didn't find an equivalent in flutter_graphql</p>