Vendor dependencies for 0.3.0 release

vendor/bevy/examples/diagnostics/custom_diagnostic.rs

@@ -0,0 +1,30 @@
+//! This example illustrates how to create a custom diagnostic.
+
+use bevy::{
+    diagnostic::{
+        Diagnostic, DiagnosticPath, Diagnostics, LogDiagnosticsPlugin, RegisterDiagnostic,
+    },
+    prelude::*,
+};
+
+fn main() {
+    App::new()
+        .add_plugins((
+            DefaultPlugins,
+            // The "print diagnostics" plugin is optional.
+            // It just visualizes our diagnostics in the console.
+            LogDiagnosticsPlugin::default(),
+        ))
+        // Diagnostics must be initialized before measurements can be added.
+        .register_diagnostic(Diagnostic::new(SYSTEM_ITERATION_COUNT).with_suffix(" iterations"))
+        .add_systems(Update, my_system)
+        .run();
+}
+
+// All diagnostics should have a unique DiagnosticPath.
+const SYSTEM_ITERATION_COUNT: DiagnosticPath = DiagnosticPath::const_new("system_iteration_count");
+
+fn my_system(mut diagnostics: Diagnostics) {
+    // Add a measurement of 10.0 for our diagnostic each time this system runs.
+    diagnostics.add_measurement(&SYSTEM_ITERATION_COUNT, || 10.0);
+}