code: function ShimCache(state, name, options) {
    this._callbacks = []
    AbstractCache.call(this, state, name, options)
  }
docs: A shim that runs a function in the context of Impromptu's caching interface.
  Does NOT cache the result!
  @constructor
  @extends {AbstractCache}
  @param {State} state
  @param {string} name The name of the cache key.
  @param {Object} options The options for this instance of the cache.