app: Use an Arc<str> for App::id

Signed-off-by: Lann Martin <lann.martin@fermyon.com>

Author: lann

Diff for: crates/app/src/lib.rs

@@ -37,14 +37,14 @@ pub type ValidatorFn = dyn Fn(&App, &[&str]) -> anyhow::Result<()>;
 /// An `App` holds loaded configuration for a Spin application.
 #[derive(Debug, Clone)]
 pub struct App {
-    id: String,
+    id: Arc<str>,
     locked: Arc<LockedApp>,
 }
 
 impl App {
     /// Returns a new app for the given runtime-specific identifier and locked
     /// app.
-    pub fn new(id: impl Into<String>, locked: LockedApp) -> Self {
+    pub fn new(id: impl Into<Arc<str>>, locked: LockedApp) -> Self {
         Self {
             id: id.into(),
             locked: Arc::new(locked),
@@ -56,6 +56,11 @@ impl App {
         &self.id
     }
 
+    /// Returns a runtime-specific identifier for this app.
+    pub fn id_shared(&self) -> Arc<str> {
+        self.id.clone()
+    }
+
     /// Deserializes typed metadata for this app.
     ///
     /// Returns `Ok(None)` if there is no metadata for the given `key` and an