stream download via HTTPBody receives broken file on Firefox

[humbornjo]

Description:

Being trying to implement connect-rpc based file upload and download service, the download behaves fine on chromium browser, but on Firefox, it only receive the first 64kb data (which is size of bufio.Writer embeded). According to the code the responseWriter won't flush until a trailer is seen. While there should exist a exception for stream HTTPBody response.

Impact:

Broken download behavior on Firefox-based browser and some cURL client (e.g. yaak). Only partial file will be downloaded.

Suggestion & Misc:

Code for Reproduce

• Should we add a alwayFlush bool in responseWriter and set it to restHTTPBodyResponse(w.op) to treat it as a exception and always flush?
• It confuses me that what is the root cause to the different behavior on Firefox and Chromium, I tried capture the net packets using wireshark, but found nothing.

[humbornjo]

related to #96