[Feature request] Ability to log timing of image loading

[bogdan]

I need to measure how fast is Kingfisher with different configuration.

I would expect onSuccess callback to provide timing information:

KFImage(url)
  onSuccess { result in {
     print("Loaded image in \(result.timing) milliseconds")
}

I don't see it causing big performance issue at least for my case, so I suggest to have enabled by default.

[darkbrewx]

I created a PR to collect network metrics and made it accessible in the success callback.
You can check out this PR and feel free to give me any feedback, and you can get the value what you want as below.

KFImage(url)
  onSuccess { result in {
     print("Loaded image in \(result. retrieveImageDuration)") // final 200 request only
     print("Loaded image in \(result. totalRequestDuration)") // includes 3xx redirects
}