如何在respondWith中取消/修改/更改/替换请求？

self.addEventListener('fetch', (event) => {
  const controller = new AbortController();
  const signal = controller.signal;

  // 取消请求
  if (/* 需要取消请求的条件 */) {
    controller.abort();
  } else {
    event.respondWith(
      fetch(event.request, { signal })
        .then((response) => {
          // 处理响应
          return response;
        })
        .catch((error) => {
          // 处理错误
          return new Response('Error occurred.', { status: 500 });
        })
    );
  }
});

self.addEventListener('fetch', (event) => {
  // 修改/更改请求
  const modifiedRequest = new Request(event.request.url, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ key: 'value' }),
  });

  event.respondWith(
    fetch(modifiedRequest)
      .then((response) => {
        // 处理响应
        return response;
      })
      .catch((error) => {
        // 处理错误
        return new Response('Error occurred.', { status: 500 });
      })
  );
});

self.addEventListener('fetch', (event) => {
  event.respondWith(
    new Response('Replacement response', {
      status: 200,
      headers: { 'Content-Type': 'text/plain' },
    })
  );
});