sdbus++: async: server: generate signal emit fns

Populate enough of the generator to define the basic class structure
and generate bindings for emitting signals.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: If62c323f460fc8c73a3aca495e5b89cd84bab32a
diff --git a/example/calculator-aserver.cpp b/example/calculator-aserver.cpp
new file mode 100644
index 0000000..220cda1
--- /dev/null
+++ b/example/calculator-aserver.cpp
@@ -0,0 +1,42 @@
+#include <net/poettering/Calculator/aserver.hpp>
+#include <sdbusplus/async.hpp>
+
+class Calculator :
+    public sdbusplus::aserver::net::poettering::Calculator<Calculator>
+{
+  public:
+    explicit Calculator(sdbusplus::async::context& ctx) :
+        sdbusplus::aserver::net::poettering::Calculator<Calculator>(
+            ctx, "/net/poettering/calculator"),
+        manager(ctx, "/")
+    {
+        ctx.spawn(startup());
+    }
+
+  private:
+    auto startup() -> sdbusplus::async::task<>
+    {
+        ctx.get_bus().request_name("net.poettering.Calculator");
+
+        while (1)
+        {
+            using namespace std::literals;
+            co_await sdbusplus::async::sleep_for(ctx, 10s);
+
+            cleared(42);
+        }
+        co_return;
+    }
+
+    sdbusplus::server::manager_t manager;
+};
+
+int main()
+{
+    sdbusplus::async::context ctx;
+    [[maybe_unused]] Calculator c(ctx);
+
+    ctx.run();
+
+    return 0;
+}