Expand navigation property on a collection with Client

[cbrianball]

I've looked over documentation and bugs, but I don't see any example of how to do this.

I am looking to generate the following OData query:
/orders?$expand=items($expand=customer)?

With the Expand method that takes a string, it is simple:
orderQuery.Expand("items($expand=customer)");

How is this accomplished with the overload that takes an expression?
orderQuery.Expand(o => o.Items); is the closest I can get. How do I then expand the Customer navigation property on each of the items?

Here's what I have tried that does NOT work.
orderQuery.Expand(o => o.Items.First().Customer);
orderQuery.Expand(o => ((DataServiceQuery<Item>)o.Items).Expand(i => i.Customer));
orderQuery.Expand(o => (o.Items as DataServiceQuery<Item>).Expand(i => i.Customer));

Any help would be appreciated.

[WanjohiSammy]

@cbrianball Thanks for posting this here. Please look at this doc https://learn.microsoft.com/en-us/odata/client/navigation-properties as we investigate further

[uffelauesen]

@cbrianball One option could be to write it as a projection, something like...

.Select(o => new Order { Items = new DataServiceCollection(o.Items.Select(i => new Item { Customer = i.Customer })) })

OData Client will translate that into a request like /Orders?$expand=Items($expand=Customer)