feat(divan_compat): add recursive fib example

Author: not-matthias

crates/divan_compat/Cargo.toml

@@ -37,3 +37,7 @@ harness = false
 [[bench]]
 name = "thread_example"
 harness = false
+
+[[bench]]
+name = "fib_example"
+harness = false

crates/divan_compat/benches/fib_example.rs

@@ -0,0 +1,26 @@
+fn fib(n: u32) -> u32 {
+    match n {
+        0 => 0,
+        1 => 1,
+        n => fib(n - 1) + fib(n - 2),
+    }
+}
+
+#[codspeed_divan_compat::bench]
+fn fib_30() -> u32 {
+    codspeed_divan_compat::black_box(fib(30))
+}
+
+#[codspeed_divan_compat::bench]
+fn fib_20() -> u32 {
+    codspeed_divan_compat::black_box(fib(20))
+}
+
+#[codspeed_divan_compat::bench]
+fn fib_10() -> u32 {
+    codspeed_divan_compat::black_box(fib(10))
+}
+
+fn main() {
+    codspeed_divan_compat::main();
+}