title: How to know if an Image is in memory in Flutter?
body: <p>I have a screen in my app with an image as the background, this image is on my asset folder. When I navigate to this screen the background is blank for an instant and then the image is loaded and it appears. This makes my screen look weird for a half a second or less, but enough for the user to notice. </p>
  
  <p>I wanted to be able to only navigate to that screen once the image is loaded (I can wait on the previous screen), so I can avoid this behavior and have the screen as a whole when the user navigates there.</p>
  
  <p>I know can make the image fade in, but that's not the experience that I want. </p>