ScrollableInkTabBar supports extraContent but get error with InkTabBar?

If I do this:

    <Tabs
      renderTabBar={() => 
        <ScrollableInkTabBar
          onTabClick={onTabClick}
          extraContent={<Button>hi</Button>}
        />
      }
...

I get the button as expected. However, if I do this:

    <Tabs
      renderTabBar={() => 
        <InkTabBar
          onTabClick={onTabClick}
          extraContent={<Button>hi</Button>}
        />
      }
...

I get an exception:

Uncaught Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.
    at createFiberFromTypeAndProps (react-dom.development.js:26629)
    at createFiberFromElement (react-dom.development.js:26652)
    at createChild (react-dom.development.js:14958)
    at reconcileChildrenArray (react-dom.development.js:15232)
    at reconcileChildFibers (react-dom.development.js:15598)
    at reconcileChildren (react-dom.development.js:18089)
    at updateHostComponent (react-dom.development.js:18611)
    at beginWork$1 (react-dom.development.js:20193)
    at HTMLUnknownElement.callCallback (react-dom.development.js:336)
    at Object.invokeGuardedCallbackDev (react-dom.development.js:385)
    at invokeGuardedCallback (react-dom.development.js:440)
    at beginWork$$1 (react-dom.development.js:25780)
    at performUnitOfWork (react-dom.development.js:24695)
    at workLoopSync (react-dom.development.js:24671)
    at performSyncWorkOnRoot (react-dom.development.js:24270)
    at react-dom.development.js:12199

Start at the InkTabBar and ScrollableInkTabBar entry points and compare how each handles the extraContent prop. Reproduce the exception with the two JSX examples, then add regression coverage where the tab-bar tests are located; done means InkTabBar renders extraContent without the invalid-element error.