title: Empty body when posting data using fetch()
body: <p>Here is my controller which is getting called, but value is always ends up null:</p>
  <pre><code> public void Post([FromBody]string value) {
   }
  </code></pre>
  <p>This is how it's being called:</p>
  <pre><code>function () {
      var data = {
          'sku': $('#radioProduct').val(),
          'qty': $('#productQty').val()
      }
      return fetch('/api/Default', {
           method: 'post',
           headers: {
                'content-type': 'application/json'
           },
           body: JSON.stringify(data)
           }).then(function (res) {
               return res.json();
           }).then(function (data) {
               return data.orderID; // Use the same key name for order ID on the client and server
           });
     }
  });
  </code></pre>
  <p>Am I doing anything wrong here?  The API does get called but the body is empty.</p>