https://github.com/cloudflare/miniflare/issues/203

We switched to using "bytes" streams but, by spec, chunks get transferred in that format. Totally reasonable. However, we pass reusable chunks which then get detached. I'm not sure why the polyfill or fixtures didn't catch this.

We really should be using the byob model instead and copy into a larger chunk for perf anyway so this just makes that more urgent.
/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 */
export type Destination = ReadableStreamController;
export type PrecomputedChunk = Uint8Array;
export type Chunk = Uint8Array;
export function scheduleWork(callback: () => void) {
  callback();
}
export function flushBuffered(destination: Destination) {