storeBlob = async (readerRef, petName) => {
      /** @type {DeferredTasks<ReadableBlobDeferredTaskParams>} */
      const tasks = makeDeferredTasks();

      if (petName !== undefined) {
        tasks.push(identifiers =>
          E(directory).write(petName, identifiers.readableBlobId),
        );
      }

      const { value } = await formulateReadableBlob(readerRef, tasks);
      return value;
    }
@param {ERef<AsyncIterableIterator<string>>} readerRef
@param {string | string[]} [petName]