HTTP headers / request & response
Connection: keep-alive
Controls whether the TCP connection survives after the response (keep-alive) or closes (close), plus which hop-by-hop headers to strip.
Forbidden in HTTP/2 — proxies translating between versions drop it, so never build logic on it.
The fastest way to see what Connection is actually doing is to send the request and read both sides raw — ReqPad shows auto-generated and custom headers for every request, on all six protocols, with history. Related references: status codes · Content-Type · Content-Length · Cache-Control · X-Request-Id
Build the request, send it, read raw headers and timing — from your iPhone. Free to start.