code: function CacheEntry(value, createdAt, lastAccessedAt){
    this.value = value;
    this.createdAt = createdAt || Date.now();
    this.lastAccessedAt = lastAccessedAt || this.createdAt;
  
    if (typeof this.createdAt !== 'number' ||
      typeof this.lastAccessedAt !== 'number'){
      throw new Error('Expecting date in timestamp format or use CacheEntry.parse method instead');
    }
  }
docs: @private
  
  @description
  
  Cache entry abstraction
  A single entry inside a cache
  
  It contains the data as originally returned by Stormpath along
  with additional metadata like timestamps.
  @param {object} value - value to store in cache
  @param {Date=} createdAt - time when cache entry created
  @param {Date=} lastAccessedAt - time when cache entry was last accessed
  @constructor