message: Fix type of DelayedPromise.toString in generated definition file.
diff: @@ -33,7 +33,7 @@ export class DelayedPromise<T> implements Promise<T> {
  }
  // We need this in order to fulfill the Promise interface defined in lib.es2015.symbol.wellknown.d.ts
  - public readonly [Symbol.toStringTag] = "Promise";
  + public readonly [Symbol.toStringTag]: "Promise" = "Promise";
  /**
  * Explicitly starts the asynchronous operation behind this DelayedPromise (if it hasn't started already).
  