remove some unused structs

src/renderer/Metal.zig

@@ -622,7 +622,7 @@ pub fn init(alloc: Allocator, options: renderer.Options) !Metal {
     };
     errdefer if (display_link) |v| v.release();
 
-    return Metal{
+    var result: Metal = .{
         .alloc = alloc,
         .config = options.config,
         .surface_mailbox = options.surface_mailbox,
@@ -663,6 +663,12 @@ pub fn init(alloc: Allocator, options: renderer.Options) !Metal {
         .custom_shader_state = custom_shader_state,
         .gpu_state = gpu_state,
     };
+
+    // Do an initialize screen size setup to ensure our undefined values
+    // above are initialized.
+    try result.setScreenSize(result.size);
+
+    return result;
 }
 
 pub fn deinit(self: *Metal) void {

src/renderer/Options.zig

@@ -20,12 +20,3 @@ surface_mailbox: apprt.surface.Mailbox,
 
 /// The apprt surface.
 rt_surface: *apprt.Surface,
-
-pub const Padding = struct {
-    // Explicit padding options, in pixels. The surface thread is
-    // expected to convert points to pixels for a given DPI.
-    explicit: renderer.Padding,
-
-    // Balance options
-    balance: bool = false,
-};