title: Setting HttpRequestMessage.Content (json) for post SendAsync results in Unexpected character error
body: <p>The setup:</p>
  
  <ol>
  <li><p>(server) .Net Core 2 API</p></li>
  <li><p>(client) AWS Lambda function coded in C# (sets the way the JWT has to be generated).</p></li>
  <li><p>IDS3 using JWT (important for method of sending the request)</p></li>
  </ol>
  
  <p>The IDS3 and JWT part are working fine. Making the call and hitting the .Net Core 2 API controller works fine.</p>
  
  <p>The problem is that I get the following error: </p>
  
  <blockquote>
    <p>Unexpected character encountered while parsing value: {. Path '', line 1, position 1.\"]</p>
  </blockquote>
  
  <p>The code, with explanations:</p>
  
  <pre><code>StringContent stringContent = new StringContent(eventStr, Encoding.UTF8, "application/json"); 
  using (HttpClient client = new HttpClient()) {
      HttpRequestMessage requestMessage = new HttpRequestMessage(HttpMethod.Post, myApiURL);
      requestMessage.Content = stringContent;
      client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", jwtToken);
      HttpResponseMessage thing = client.SendAsync(requestMessage).Result;
      string actualResponse = thing.Content.ReadAsStringAsync().Result;        
  }
  </code></pre>
  
  <p><code>eventStr</code> is a json string passed to the function handler by AWS. </p>
  
  <p><code>actualResponse</code> contains the erropr: <code>Unexpected character encountered while parsing value: {. Path '', line 1, position 1.\"]</code></p>
  
  <p>I've checked the StringContent being generated and it is absolutely correct.</p>
  
  <p>What happens on the API side of things is that the JWT is found to be awesomely correct, the Controller constructor is fired, the action is never hit, ostensibly because the data payload (eventStr) isn't being attached to the <code>HttpRequestMessage</code> correctly.</p>
  
  <p>Method signature for the API action: </p>
  
  <pre><code>          public async Task&lt;ActionResult&gt; Post([FromBody] string Message)
  </code></pre>
  
  <p>If that's not the right place, what is? </p>