@dmeremyanin Hey, thanks for this. Could you rebase onto current main?

Hey, couple of things:

1. The blob.text().then(hook) isn't returned into the chain, so it's fire-and-forget. The next .then() (which fires onMeasurementResult) runs before the hook finishes. LoggingBandwidthEngine uses this hook to extract a token that onMeasurementResult needs — so there's a race condition. Need to return the promise so the chain waits for it.

something like this should work:

.then(r =>
  r.blob().then(blob => {
    if (this.#responseHook) {
      return blob.text().then(body => {
        this.#responseHook({ url, headers: r.headers, body });
        return blob;
      });
    }
    return blob;
  })
)

The key difference is return blob.text().then(...) — returning the promise so the chain waits for the hook to finish before continuing to the timing calculation.

2. That detached promise also has no .catch() — errors get swallowed silently.

3. Minor: #responseHook defaults to r => r, not null, so the if guard is always true. blob.text() runs every time regardless.