Still keep the placeholder arg, this may be useful for common usage like image name placeholder

Author: dreampiggy

SDWebImageSwiftUI/Classes/WebImage.swift

@@ -26,12 +26,16 @@ public struct WebImage : View {
 
     /// Create a web image with url, placeholder, custom options and context.
     /// - Parameter url: The image url
+    /// - Parameter placeholder: The placeholder image to show during loading
     /// - Parameter options: The options to use when downloading the image. See `SDWebImageOptions` for the possible values.
     /// - Parameter context: A context contains different options to perform specify changes or processes, see `SDWebImageContextOption`. This hold the extra objects which `options` enum can not hold.
-    public init(url: URL?, options: SDWebImageOptions = [], context: [SDWebImageContextOption : Any]? = nil) {
+    public init(url: URL?, placeholder: Image? = nil, options: SDWebImageOptions = [], context: [SDWebImageContextOption : Any]? = nil) {
         self.url = url
         self.options = options
         self.context = context
+        if let placeholder = placeholder {
+            self.placeholder = AnyView(placeholder)
+        }
         self.imageManager = ImageManager(url: url, options: options, context: context)
         // load remote image here, SwiftUI sometimes will create a new View struct without calling `onAppear` (like enter EditMode) :)
         // this can ensure we load the image, SDWebImage take care of the duplicated query