code: function() {
          const roomKeys = getKeysWithPrefix(this.store, keyEndToEndRoom(''));
          const results = {};
          for (const k of roomKeys) {
              const unprefixedKey = k.substr(keyEndToEndRoom('').length);
              results[unprefixedKey] = getJsonItem(this.store, k);
          }
          return results;
      }
docs: Get the end-to-end state for all rooms
  @return {object} roomId -> object with the end-to-end info for the room.