Implemented window title update functionality for multiwindow.

native/src/window/id.rs

@@ -1,15 +1,18 @@
 use std::collections::hash_map::DefaultHasher;
+use std::fmt::{Display, Formatter};
 use std::hash::{Hash, Hasher};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
-/// TODO(derezzedex)
+/// The ID of the window.
+///
+/// This is not necessarily the same as the window ID fetched from `winit::window::Window`.
 pub struct Id(u64);
 
 impl Id {
     /// TODO(derezzedex): maybe change `u64` to an enum `Type::{Single, Multi(u64)}`
     pub const MAIN: Self = Id(0);
 
-    /// TODO(derezzedex)
+    /// Creates a new unique window ID.
     pub fn new(id: impl Hash) -> Id {
         let mut hasher = DefaultHasher::new();
         id.hash(&mut hasher);
@@ -17,3 +20,9 @@ impl Id {
         Id(hasher.finish())
     }
 }
+
+impl Display for Id {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Id({})", self.0)
+    }
+}