title: SwiftUI: Kingfisher using KFImage can display erroneous semitransparent image
body: <p>I am using KFImage to asynchronously load images in SwiftUI views including List rows. 
  Sometimes it happens that when scrolling rows and there are I think some cell reusing or refreshes KFImage image displayed is made with a little semitransparency and it stays.<br>
  I have such code: </p>
  
  <pre><code>KFImage(URL(string: self.host + "/image.png"))
              .resizable()
              .placeholder {
                  self.makeInitialsView()
              }
              .cancelOnDisappear(true)
              .aspectRatio(contentMode: .fill)
              .frame(width: 25, height: 25)
              .clipShape(Circle())
  </code></pre>
  
  <p>I suppose it can be some error in KFImage, but I do not know whether KFImage component or Kingfisher library has such behaviour to display image sometimes with semitransparency for instance to indicate loading image or something else.</p>
  
  <p>it is used in swiftui list like: </p>
  
  <pre><code>List { 
    ForEach(items, id: \.self) { item { 
       ItemRow(item: item)
    }
  }
  
  ItemRow { 
     var body: some View {
  
          HStack(alignment: .top) {
  
  
              self.makeAvatar()
  
  
              VStack(alignment: .leading) {
                 Text("Some text")
             }
        }
     }
  }
  </code></pre>