feature request: `transformRequest` must be able to be asynchronous

interceptor may be async => https://github.com/axios/axios/blob/main/index.d.cts#L514

for example

axios.interceptors.request.use(async (config) => {
  try {
    // Simulate an async call (e.g., getting a token from storage or an API)
    const token = await getAuthToken(); 
    
    // Modify headers
    config.headers['Authorization'] = `Bearer ${token}`;
    
    return config;
  } catch (error) {
    return Promise.reject(error);
  }
});

the same behavior is needed in transformRequest