Repro: https://codesandbox.io/s/fast-water-4i4jb

Notice the flash. I'd expect `suspended` to be `true` during the high pri render.
workInProgress,
          renderExpirationTime,
        );
      }
      break;
    }
    case Block: {
      if (enableBlocksAPI) {
        const block = workInProgress.type;
        const props = workInProgress.pendingProps;
        return updateBlock(
          current,
          workInProgress,
          block,
          props,
          renderExpirationTime,
        );
      }
      break;
    }
  }
  invariant(
    false,
    'Unknown unit of work tag (%s). This error is likely caused by a bug in ' +
      'React. Please file an issue.',
    workInProgress.tag,
  );
}
export {beginWork};