Sitecore GraphQL best practices

// the <ItemState> determines the data object type this graph type maps to
// (in a resolver, context.Source is of this type)
public class ItemWorkflowGraphType : ObjectGraphType<ItemState>
{
    public ItemWorkflowGraphType()
    {
        // ALWAYS set the name. Note that the name must be unique within a schema so be descriptive.
        Name = "ItemWorkflow"; 

        // define your field (note: wrap type in NonNullGraphType<T> if it should never be null)
        Field<ItemWorkflowStateGraphType>("workflowState", resolve: ResolveWorkflowState);

        // this would automatically map to a property on the ItemState called WorkflowState
        // DO NOT use this format, because it causes reflection during queries = slow
        Field<ItemWorkflowStateGraphType>("workflowState");

        // Expression-based resolver. Reasonable performance, non-verbose, but cannot specify
        // the graph type (or its nullablilty), and you do not get nice stack traces on error
        // useful for very simple scalar type resolution (e.g. strings, ints)
        Field("workflowState", state => GetWorkflowState());

        // Sometimes you might not have access to the Field() method, in which case 
        // you can use manual field-adding syntax. This example is equivalent to the first recommended one.
        // Note: DO NOT set the ResolvedType property by accident. This will mess things up.
        AddField(new FieldType
        {
            Name = "workflowState",
            Type = typeof(ItemWorkflowStateGraphType),
            Resolver = new FuncFieldResolver<ItemState, WorkflowState>(ResolveWorkflowState)
        });
    }

    // explicit named resolver function means that you will see a reasonable stack trace if a resolve error occurs
    // (as oppposed to an anonymous function in the constructor)
    private WorkflowState ResolveWorkflowState(ResolveFieldContext<ItemState> context)
    {
        return context.Source.GetWorkflowState();
    }
}