Your JSON Array Was Streaming All Along

I set out to prove a code-review comment right. The stopwatch had other plans.

Code review last week: a progress endpoint for a long import job, returning IAsyncEnumerable<Step> from a minimal API. The comment under it said what I'd have written myself a month ago: "JSON responses buffer, the client won't see anything until the job finishes. Use SignalR." I've repeated that advice for years without once pointing a stopwatch at it. So before approving, I did.

The rig

One minimal API, one fake job that yields a step every 400 ms:

app.MapGet("/steps/json", (CancellationToken ct) => Produce(padding: 0, ct));