title: Process connection_type after resolved
body: <p>I use graphql gem 1.8.11.</p>
  
  <p>My <code>UserType</code> has <code>notifications</code> connection field and if it is queried I'd like to perform some operation (<code>read!</code> in example below).</p>
  
  <p>Example below performs the operation for all of association field.
  Even if <code>notifications</code> field has pagination parameter and not all of <code>notifications</code> are queried, the operation is performed for all <code>notifications</code>.</p>
  
  <p>How can I perform the operation only for queried nodes?</p>
  
  <pre><code>module Types
    class UserType &lt; Types::BaseObject
      implements GraphQL::Relay::Node.interface
  
      field :id, ID, null: false
      field :notifications, NotificationType.connection_type, null: true
  
      global_id_field :id
  
  
      def notifications
        object.notifications.tap { |o| o.read! }
      end
    end
  end
  </code></pre>