message: Explicitly export members of fluidRouter to workaround Typescript issue
  When downstream customers augment the IRequestHeader, the [index: string]: any; signature is lost and they end up with "property does not exist" errors.
  This change uses this workaround to resolve the issue:
  microsoft/TypeScript#18877 (comment)
diff: export { IFluidObject } from "./fluidObject";
  export * from "./fluidLoadable";
  -export * from "./fluidRouter";
  +// Typescript forgets the index signature when customers augment IRequestHeader if we export *.
  +// So we export the explicit members as a workaround:
  +// https://github.com/microsoft/TypeScript/issues/18877#issuecomment-476921038
  +export {
  + IRequest,
  + IRequestHeader,
  + IResponse,
  + IProvideFluidRouter,
  + IFluidRouter,
  +} from "./fluidRouter";
  export * from "./handles";
  export * from "./serializer";
  export * from "./fluidPackage";
  