code: public function upload($file, Closure $callback = null)
      {
          $uploadedFile = $this->runUpload($file);
  
          if (! $uploadedFile) {
              return false;
          }
  
          if ($callback) {
              $callback($uploadedFile);
          }
  
          return true;
      }
docs: Upload the file on a file storage.
  
  @param  string  $file
  @param  \Closure|null $callback
  @return bool