Content to display during a particular state of a Glide Request, for example while the request is loading or if the request fails.

of(Drawable) and of(resourceId) trigger fewer recompositions than of(@Composable () -> Unit) so you should only use the Composable variant if you require something more complex than a simple color or a static image.

of(@Composable () -> Unit) will display the Composable inside a Box whose modifier is the one provided to GlideImage. Doing so allows Glide to infer the requested size if one is not explicitly specified on the request itself.