code: function addBody(options, body) {
      return {
          body: body,
          headers: options.headers,
          observe: options.observe,
          params: options.params,
          reportProgress: options.reportProgress,
          responseType: options.responseType,
          withCredentials: options.withCredentials,
      };
  }
docs: @license
  Copyright Google Inc. All Rights Reserved.
  
  Use of this source code is governed by an MIT-style license that can be
  found in the LICENSE file at https://angular.io/license
   
  Construct an instance of `HttpRequestOptions<T>` from a source `HttpMethodOptions` and
  the given `body`. Basically, this clones the object and adds the body.