Calculating a cross-partition aggregate with an asynchronous LINQ query

The following lines declare the code for the DoesCompetitionWithTitleExistWithLinq asynchronous static method, which builds a LINQ query to count the number of competitions with the received title. In order to compute this aggregate, we must run a cross-partition query, because the title for the competition can be at any location; that is, at any zip code.

Add the following lines to the existing code of the Program.cs file. The code file for the sample is included in the learning_cosmos_db_05_01 folder in the SampleApp2/SampleApp1/Program.cs file:

private static async Task<bool> DoesCompetitionWithTitleExistWithLinq(string competitionTitle) 
{ 
    var competitionsCount = await client.CreateDocumentQuery<Competition>(collectionUri, 
        new FeedOptions() 
        { 
            EnableCrossPartitionQuery = true, 
            MaxItemCount = 1, 
        }) 
        .Where(c => c.Title == competitionTitle...