title: "Multithreaded execution was detected" when using context.CallHttpAsyn
body: <p>I have an OrchestrationTrigger function that call another service by http request.</p>
  
  <pre><code> [FunctionName("MyFunc")]
          public async Task RunOrchestrator(
          [OrchestrationTrigger] IDurableOrchestrationContext context,
          ILogger logger)
      {
          var req = new DurableHttpRequest(HttpMethod.Post, _uri, headers, jsonBody);
          var res = await context.CallHttpAsync(req);
          // Do something
      }
  </code></pre>
  
  <p>but get the following error: </p>
  
  <blockquote>
    <p>Multithreaded execution was detected. This can happen if the
    orchestrator function code awaits on a task that was not created by a
    DurableOrchestrationContext method. More details can be found in this
    article
    <a href="https://docs.microsoft.com/en-us/azure/azure-functions/durable-functions-checkpointing-and-replay#orchestrator-code-constraints" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/azure/azure-functions/durable-functions-checkpointing-and-replay#orchestrator-code-constraints</a>.</p>
  </blockquote>
  
  <p>the official documentation there suggest to use  <code>context.CallHttpAsync</code> - exactly what I've did.</p>