feat(runtime_example): add example of hot reloading in the Mun Runtime

crates/mun_runtime/examples/hot_reloading.rs

@@ -0,0 +1,22 @@
+use mun_runtime::{invoke_fn, RetryResultExt, RuntimeBuilder};
+use std::env;
+
+// How to run?
+// 1. On the CLI, navigate to the `crates/mun_runtime/examples` directory.
+// 2. Run the compiler daemon from the CLI: `/path/to/mun build resources/fibonacci.mun --watch`
+// 3. Run the application from the CLI: cargo run --example hot_reloading -- fibonacci.dll
+fn main() {
+    let lib_dir = env::args().nth(1).expect("Expected path to a Mun library.");
+    println!("lib: {}", lib_dir);
+
+    let mut runtime = RuntimeBuilder::new(lib_dir)
+        .spawn()
+        .expect("Failed to spawn Runtime");
+
+    loop {
+        let n: i64 = invoke_fn!(runtime, "nth").wait();
+        let result: i64 = invoke_fn!(runtime, "fibonacci", n).wait();
+        println!("fibonacci({}) = {}", n, result);
+        runtime.update();
+    }
+}

crates/mun_runtime/examples/resources/fibonacci.mun

@@ -0,0 +1,11 @@
+fn nth(): int {
+    3
+}
+
+fn fibonacci(n:int):int {
+    if n <= 1 {
+        n
+    } else {
+        fibonacci(n-1) + fibonacci(n-2)
+    }
+}