code: function makePostCorsRequest (url, data) {
          var xhr = createCORSRequest('POST', url, data);
  
          if (typeof _beforeXHRCallback === 'function') {
              _beforeXHRCallback(xhr);
          }
  
          if ('withCredentials' in xhr) {
  
              xhr.onreadystatechange = function() {
                  if (xhr.readyState !== 4) {
                      return;
                  }
  
                  if (xhr.status === 202) {
                      sendSavedErrors();
                  } else if (_enableOfflineSave && xhr.status !== 403 && xhr.status !== 400 && xhr.status !== 429) {
                      offlineSave(url, data);
                  }
              };
  
              xhr.onload = function() {
                  _private.log('posted to Raygun');
  
                  callAfterSend(this);
              };
  
          } else if (window.XDomainRequest) {
              xhr.ontimeout = function() {
                  if (_enableOfflineSave) {
                      _private.log('Raygun: saved locally');
                      offlineSave(url, data);
                  }
              };
  
              xhr.onload = function() {
                  _private.log('posted to Raygun');
  
                  sendSavedErrors();
                  callAfterSend(this);
              };
          }
  
          xhr.onerror = function() {
              _private.log('failed to post to Raygun');
  
              callAfterSend(this);
          };
  
          if (!xhr) {
              _private.log('CORS not supported');
              return;
          }
  
          xhr.send(data);
      }
docs: Make the actual CORS request.