Azure Cosmos DB + Functions Cookbook: static client (wrong scenario)

wrong-run.csx

#r "Microsoft.Azure.Documents.Client"
using Microsoft.Azure.Documents;
using Microsoft.Azure.Documents.Client;
using System.Net;

private static string endpointUrl = ConfigurationManager.AppSettings["cosmosDBAccountEndpoint"]; 
private static string authorizationKey = ConfigurationManager.AppSettings["cosmosDBAccountKey"]; 

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    // Avoid doing this!
    using (DocumentClient client = new DocumentClient(new Uri(endpointUrl), authorizationKey)){ 
        string id = req.GetQueryNameValuePairs()
            .FirstOrDefault(q => string.Compare(q.Key, "id", true) == 0)
            .Value;
        if (string.IsNullOrEmpty(id)){
          return req.CreateResponse(HttpStatusCode.BadRequest);
        }

        Uri documentUri = UriFactory.CreateDocumentUri("name of database","name of collection",id);
        Document doc = await client.ReadDocumentAsync(documentUri);

        if (doc == null){
          return req.CreateResponse(HttpStatusCode.NotFound);
        }

        return req.CreateResponse(HttpStatusCode.OK, doc);
    }
}