Feat: Trying to add a reload api for Coil

[whitescent]

This PR is trying to fix #884 #132

I use coil in my social apps, but in some cases, pictures may fail to load. I need to tell users and let them manually try to refresh or let coil reload pictures automatically. However, coil has not provided relevant api yet. After I checked # 884, I want to decide to try to submit a PR for coil to complete this function.

But the implementation is a bit rudimentary, and I'm trying to do it mainly with your public API idea under #884 comment

Now the general way to use it is like this:

if use AsyncImage and want to retry:

val requestHandle = rememberAsyncImageRequestHandle()
Box {
  var loadState by remember { mutableStateOf<State>(Empty) }
  AsyncImage(
      model = ImageRequest.Builder(LocalContext.current)
          .data(image.uri)
          .parameters(image.parameters)
          .build(),
      requestHandle = requestHandle,
      placeholder = ColorPainter(Color(image.color)),
      error = ColorPainter(Color.Red),
      onSuccess = {
          loadState = it
          placeholder = it.result.memoryCacheKey
      },
      onError = {
          loadState = it
      },
      onLoading = {
          loadState = it
      },
      contentDescription = null,
      contentScale = ContentScale.Crop,
      modifier = Modifier
          .size(size)
          .clickable { onImageClick(image, placeholder) }
  )
  LaunchedEffect(Unit) {
      snapshotFlow { loadState }
          .distinctUntilChanged()
          .filter { it is State.Error }
          .collect {
              requestHandle.retry()
              delay(3000)
          }
  }

demo.mp4

Although this does allow coil to reload images, the implementation is not very elegant

if use AsyncImagePainter :

val painter = rememberAsyncImagePainter(
    model = ImageRequest.Builder(LocalContext.current)
        .data(image.uri)
        .parameters(image.parameters)
        .requestHandle(requestHandle)
        .build()
)
Box(contentAlignment = Alignment.Center) {
    Image(
        painter = painter,
        contentDescription = null,
        contentScale = ContentScale.Crop,
        modifier = Modifier
            .size(size)
            .clickable { onImageClick(image, placeholder) }
    )
    when (val state = painter.state) {
        is AsyncImagePainter.State.Error -> {
            // we can manually trigger recomposition here to
            // try to reload the image
            Button(onClick = { requestHandle.retry() }) { Text("retry") }
        }
        is AsyncImagePainter.State.Success -> placeholder = state.result.memoryCacheKey
        is AsyncImagePainter.State.Loading ->
            CircularProgressIndicator(Modifier.size(36.dp), color = Color.Blue)
        else -> Unit
    }
}

demo2.mp4

Since I'm not sure if AsyncImage has become stable, it's not clear if it's a good time to implement the reload api, but maybe we can discuss more specific api design & implementation here :)