function(cacheName, key, val) {
    var cache = this.cache(cacheName);
    cache.set(key, val);
    return cache;
  }
function(cacheName, key, val) {
    var cache = this.cache(cacheName);
    cache.set(key, val);
    return cache;
  }
function ( cacheName , key , val ) { var cache = this . cache ( cacheName ) ; cache . set ( key , val ) ; return cache ; }
Set a value for property `key` on cache `name`

```js
fragment.set('files', 'somefile.js', new File({path: 'somefile.js'}));
```
@name .set
@param {String} `name`
@param {String} `key` Property name to set
@param {any} `val` The value of `key`
@return {Object} The cache instance for chaining
@api public
Set a value for property key on cache name