Truncate breadcrumb values (right now just URLs)
function _trimBreadcrumbs(breadcrumbs) {
	    // known breadcrumb properties with urls
	    // TODO: also consider arbitrary prop values that start with (https?)?://
	    var urlProps = ['to', 'from', 'url'],
	        urlProp,
	        crumb,
	        data;

	    for (var i = 0; i < breadcrumbs.values.length; ++i) {
	      crumb = breadcrumbs.values[i];
	      if (!crumb.hasOwnProperty('data') || !isObject$1(crumb.data) || objectFrozen$1(crumb.data)) continue;
	      data = objectMerge$1({}, crumb.data);

	      for (var j = 0; j < urlProps.length; ++j) {
	        urlProp = urlProps[j];

	        if (data.hasOwnProperty(urlProp) && data[urlProp]) {
	          data[urlProp] = truncate$1(data[urlProp], this._globalOptions.maxUrlLength);
	        }
	      }

	      breadcrumbs.values[i].data = data;
	    }
	  }