Build a useful investigation brief
Choose contrasting fixtures
Use a small file, a multi-chunk file, and a file whose final range is short. Record total bytes and expected percentages at each boundary. Include a case where transfer continues during a quiet interval so event absence is observable.
Align event streams
Place local progress events, receiver acknowledgments, request responses, rendered values, and phase changes on one timeline. Check whether the denominator includes only transfer bytes or later work, and whether a final response resets or advances the value.
Write the signal boundary
Identify the first event where measured bytes, calculated percentage, or rendered phase diverges from the contract. Explain the observed result with arithmetic and timing, and leave an unobserved transport cause as a hypothesis.
What to carry forward
The investigation is sufficient when a fixture and aligned timeline reproduce the stalled or premature value and identify its first divergence. If the bytes cannot be observed, document the presentation gap separately from any claim that transfer progress stopped.
Technical background: MDN reference.
Keep the decision with the work.
Use a Work Item in Aglet to record the problem, the evidence you have, and the next decision. Add an owner and priority, then keep updates in the discussion so the next person can follow the reasoning.
Create an account See the product workflow