mod(memory): do not create items on the stack instead using the provided allocator

src/layout/VStack.zig

@@ -30,11 +30,12 @@ pub fn Layout(comptime Event: type, comptime Element: type, comptime Renderer: t
     const Events = std.ArrayList(Event);
     return struct {
         // TODO: current focused `Element`?
-        size: terminal.Size = undefined,
-        elements: Elements = undefined,
-        events: Events = undefined,
+        allocator: std.mem.Allocator,
+        size: terminal.Size,
+        elements: Elements,
+        events: Events,
 
-        pub fn init(allocator: std.mem.Allocator, children: anytype) @This() {
+        pub fn init(allocator: std.mem.Allocator, children: anytype) *@This() {
             const ArgsType = @TypeOf(children);
             const args_type_info = @typeInfo(ArgsType);
             if (args_type_info != .@"struct") {
@@ -55,10 +56,11 @@ pub fn Layout(comptime Event: type, comptime Element: type, comptime Renderer: t
                 }
                 @compileError("child: " ++ field.name ++ " is not of type " ++ @typeName(WidgetType) ++ " or " ++ @typeName(LayoutType) ++ " but " ++ @typeName(ChildType));
             }
-            return .{
-                .elements = elements,
-                .events = Events.init(allocator),
-            };
+            var this = allocator.create(@This()) catch @panic("VStack.zig: Failed to create.");
+            this.allocator = allocator;
+            this.elements = elements;
+            this.events = Events.init(allocator);
+            return this;
         }
 
         pub fn deinit(this: *@This()) void {
@@ -74,6 +76,7 @@ pub fn Layout(comptime Event: type, comptime Element: type, comptime Renderer: t
                 }
             }
             this.elements.deinit();
+            this.allocator.destroy(this);
         }
 
         pub fn handle(this: *@This(), event: Event) !*Events {