Azure Functions（isolated）でApplication Insightsの分散トレーシングを取得する

    public static void Main()
    {
        var host = new HostBuilder()

            .ConfigureAppConfiguration(builder =>
            {
                builder.AddAzureAppConfiguration(options =>
                {
                    options.Connect(appcs_con_string);
                });
            })
            .ConfigureServices(s =>
            {
　　　　　　　　  // HttpClientの登録
                s.AddHttpClient();

　　　　　　　　　// Application Insights用に下記2つを追加する
                s.AddApplicationInsightsTelemetryWorkerService();
                s.ConfigureFunctionsApplicationInsights();

                //CosmosDBクライアントの登録
                s.AddSingleton(serviceProvider =>
                {
                    return new CosmosClient(endpoint, key);
                });
            })
            .ConfigureFunctionsWorkerDefaults(app =>
            {
                app.UseAzureAppConfiguration();
            })
            .Build();
        host.Run();
    }

        public Test1(ILoggerFactory loggerFactory, IHttpClientFactory httpClientFactory, TelemetryClient telemetryClient, CosmosClient cosmosClient)
        {
            _logger = loggerFactory.CreateLogger<Test1>();
            _cosmosClient = cosmosClient;
            _httpClient = httpClientFactory.CreateClient();
            _telemetryClient = telemetryClient;
        }

        [Function("Test1")]
        public async Task<HttpResponseData> Run([HttpTrigger(AuthorizationLevel.Function, "get", "post")] HttpRequestData req)
        {

            var res = new US();
            try
            {
                // 外部API呼び出し
                var request = new HttpRequestMessage(HttpMethod.Get, uri);
                var apiResponse = await _httpClient.SendAsync(request);
                var body = await apiResponse.Content.ReadAsStringAsync();
                res = JsonSerializer.Deserialize<US>(body);

                // CosmosDBへの読み取り
                var con = _cosmosClient.GetContainer(containerName, colletionName);
                var readResult = await con.ReadItemAsync<CosmosEntity>(id, new PartitionKey(id));

            }
            catch (Exception ex)
            {
                _logger.LogCritical(ex.Message);
            }
 
            var response = req.CreateResponse(HttpStatusCode.OK);
            response.Headers.Add("Content-Type", "text/plain; charset=utf-8");
            response.WriteString($"{res?.data.First().Population}");
            return response;
        }

    {
        "ApplicationInsights":
        {
            "ConnectionString" : "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
        },
        "Logging":
        {
            "LogLevel":
            {
                "Default": "Warning"
            }
    }

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "",
    "FUNCTIONS_WORKER_RUNTIME": "dotnet-isolated",
    "APPLICATIONINSIGHTS_CONNECTION_STRING": "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
  }
}