Certificate pinning has no shared implementation, and should not
Each engine pins through its own trust machinery, and one cannot pin at all.
networking
6 posts
Ktor plugin order is not style — it decides what gets retried
Install auth after retry and a refresh happens per attempt; before, once.
The multipart upload that worked on three engines
Streaming a file body needs a filesystem, and one target has none.
Your HTTP cache exists on two targets and is a stub on two others
OkHttp and NSURLSession cache to disk, the browser's cache is the browser's, and the common engine has none. Measured hit rates differ by a factor nobody budgeted for.
Nothing reconnects your WebSocket, on any target
A dropped socket is a normal event with no exception on some engines. Reconnection with jitter and a resume token is application code, and it is the same code on all four.
One Ktor client, four engines, and the timeouts that don't mean the same thing
You configure one connect timeout. OkHttp, NSURLSession and the browser each enforce a different thing with it.