function Stats(proton) {
      this.proton = proton;
      this.container = null;
      this.type = 1;
      this.emitterIndex = 0;
      this.rendererIndex = 0;
    }
Returns Pool.cache

@method getCache
@memberof Proton#Proton.Pool
@private

@param {Number} uid the unique id

@return {Object}