chore: add example with allocations

Author: not-matthias

crates/divan_compat/examples/Cargo.toml

@@ -44,3 +44,7 @@ harness = false
 [[bench]]
 name = "counters"
 harness = false
+
+[[bench]]
+name = "alloc"
+harness = false

crates/divan_compat/examples/benches/alloc.rs

@@ -0,0 +1,38 @@
+use std::{
+    alloc::Layout,
+    collections::{HashMap, HashSet},
+};
+
+#[divan::bench]
+fn allocate() {
+    println!("Hello, world!");
+
+    let vec = vec![1, 2, 3];
+    println!("{vec:?}");
+
+    let mut map = HashMap::new();
+    map.insert("key", "value");
+    println!("{map:?}");
+
+    let mut set = HashSet::new();
+    set.insert("apple");
+    set.insert("banana");
+    println!("{set:?}");
+
+    std::thread::sleep(std::time::Duration::from_secs(1));
+
+    let mut bytes_vec = vec![0u8; 0x100];
+    println!("{:?}", bytes_vec.len());
+
+    bytes_vec.extend(&vec![0u8; 0x1000]);
+
+    // Alloc 256 bytes of memory
+    for _ in 0..100 {
+        let memory = unsafe { std::alloc::alloc(Layout::new::<[u8; 42]>()) };
+        core::hint::black_box(memory);
+    }
+}
+
+fn main() {
+    divan::main();
+}