improv: create subscription channel for pages to send messages to

page/Cargo.toml

@@ -11,4 +11,5 @@ libcosmic = { workspace = true }
 generator = "0.7.5"
 downcast-rs = "1.2.0"
 once_cell = "1.19.0"
-url = "2.5.0"
+tokio.workspace = true
+url = "2.5.0"

page/src/binder.rs

@@ -166,9 +166,13 @@ impl<Message: 'static> Binder<Message> {
     }
 
     /// Calls a page's load function to refresh its data.
-    pub fn page_reload(&mut self, id: crate::Entity) -> Command<Message> {
+    pub fn on_enter(
+        &mut self,
+        id: crate::Entity,
+        sender: tokio::sync::mpsc::Sender<Message>,
+    ) -> Command<Message> {
         if let Some(page) = self.page.get_mut(id) {
-            return page.reload(id);
+            return page.on_enter(id, sender);
         }
 
         Command::none()

page/src/lib.rs

@@ -59,9 +59,12 @@ pub trait Page<Message: 'static>: Downcast {
     }
 
     /// Reload page metadata via a Command.
-    #[must_use]
     #[allow(unused)]
-    fn reload(&mut self, page: crate::Entity) -> Command<Message> {
+    fn on_enter(
+        &mut self,
+        page: crate::Entity,
+        sender: tokio::sync::mpsc::Sender<Message>,
+    ) -> Command<Message> {
         Command::none()
     }