Build a useful investigation brief
Create a patterned document
Use bytes that identify their position and a length spanning full ranges plus a remainder. Record expected total length and boundary requests, then create partial files after an early, middle, and final-range interruption.
Trace resume requests
Capture local retained length, requested start and end, response range, response length, revision identity, and append decision. Compare each response with the source slice and mark any mismatch before it reaches the assembled file.
Rebuild the output independently
Assemble recorded partial and response bytes outside the download flow, compare them with the source, and identify the earliest gap or overlap. Test a revision change separately and state whether persistent local state remains an unproven cause.
What to carry forward
The investigation is sufficient when a patterned fixture and range trace identify the first incorrect append or identity boundary. Stop at that boundary and preserve the arithmetic; later corruption is a consequence until separate evidence shows otherwise.
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