message: Expose export for CombinedError
diff: @@ -13,6 +13,7 @@ export * from './components/connect-hoc';
  export * from './modules/query';
  export * from './modules/cache-exchange';
  export * from './modules/dedup-exchange';
  +export * from './modules/error';
  export * from './modules/http-exchange';
  export * from './modules/subscription-exchange';
  