Add example of suspended coroutines

examples/suspended_coroutines/src/main.rs

@@ -0,0 +1,33 @@
+extern crate bdwgc_alloc;
+extern crate coroutine;
+
+use bdwgc_alloc::Allocator;
+use coroutine::asymmetric::Coroutine;
+use std::alloc::Layout;
+
+#[global_allocator]
+static GLOBAL_ALLOCATOR: Allocator = Allocator;
+
+fn main() {
+    unsafe { Allocator::initialize() }
+
+    Allocator::disable_gc();
+    let mut handle = Coroutine::spawn(move |me, _| {
+        let bottom: u8 = 0;
+        unsafe { Allocator::set_stack_bottom(&bottom) }
+        Allocator::enable_gc();
+
+        me.yield_with(42);
+        unsafe { Allocator::set_stack_bottom(&bottom) }
+        Allocator::enable_gc();
+
+        loop {
+            unsafe { std::alloc::alloc(Layout::from_size_align(2 ^ 8, 8).unwrap()) };
+        }
+    });
+
+    Allocator::disable_gc();
+    assert_eq!(handle.resume(0).unwrap(), 42);
+
+    handle.resume(0).unwrap();
+}