Next.js has this headers function in the next.config.js file. For example:

/** @type {import('next').NextConfig} */
module.exports = {
  async headers() {
    return [
      {
        // matching all API routes
        source: "/api/:endpoint*",
        headers: [ ... ]
      }
    ];
  }
};

But these headers are defined when the app is initializing. How can I set headers per request, as I need to set the value from @fingerprintjs/fingerprintjs when Next.js performs API calls.

I am aware that I can directly use fetch, but I also need this header to be present when Next Auth performs API calls, etc.