code: function _setHeaders( request, options ) {
  	// If there's no headers, do nothing
  	if ( ! options.headers ) {
  		return request;
  	}
  
  	return objectReduce(
  		options.headers,
  		( request, value, key ) => request.set( key, value ),
  		request
  	);
  }
docs: Set any provided headers on the outgoing request object. Runs after _auth.
  
  @method _setHeaders
  @private
  @param {Object} request A superagent request object
  @param {Object} options A WPRequest _options object
  @param {Object} A superagent request object, with any available headers set