diff --git a/a8/awaiter.cc b/a8/awaiter.cc
new file mode 100644
index 0000000..d9db7b8
--- /dev/null
+++ b/a8/awaiter.cc
@@ -0,0 +1,31 @@
+#include <a8/a8.h>
+
+#include <a8/awaiter.h>
+
+namespace a8
+{
+
+    void Awaiter::Await(std::shared_ptr<Awaiter> notifyer)
+    {
+        notifyers_.push_back(notifyer);
+        DoAwait();
+    }
+
+#if 0
+    std::shared_ptr<Awaiter> Awaiter::Sleep(int time)
+    {
+        return std::make_shared<TimerPromise>(time);
+    }
+#endif
+
+    void Awaiter::DoDone()
+    {
+        done_ = true;
+        for (auto notifyer : notifyers_) {
+            if (!notifyer.expired()) {
+                notifyer.lock()->DoResume();
+            }
+        }
+    }
+
+}
diff --git a/a8/awaiter.h b/a8/awaiter.h
new file mode 100644
index 0000000..b7d09ff
--- /dev/null
+++ b/a8/awaiter.h
@@ -0,0 +1,37 @@
+#pragma once
+
+#include <a8/result.h>
+
+namespace f8
+{
+    class Coroutine;
+}
+
+namespace a8
+{
+
+    class Awaiter : public std::enable_shared_from_this<Awaiter>
+    {
+    public:
+        virtual ~Awaiter() {};
+
+        std::shared_ptr<a8::Results> GetResult() { return results_; }
+        bool Done() const { return done_; }
+        virtual void DoResume() {};
+
+    protected:
+        bool done_ = false;
+
+        std::list<std::weak_ptr<Awaiter>> notifyers_;
+        void Await(std::shared_ptr<Awaiter> notifyer);
+        virtual void DoAwait() = 0;
+        void DoDone();
+
+    private:
+        std::shared_ptr<a8::Results> results_;
+        std::function<void()> cb_;
+
+        friend class f8::Coroutine;
+    };
+
+}
diff --git a/a8/promise.h b/a8/promise.h
new file mode 100644
index 0000000..b602e28
--- /dev/null
+++ b/a8/promise.h
@@ -0,0 +1,10 @@
+#pragma once
+
+namespace a8
+{
+
+    class Promise : public Awaiter
+    {
+    };
+
+}
diff --git a/a8/result.h b/a8/result.h
new file mode 100644
index 0000000..950f41a
--- /dev/null
+++ b/a8/result.h
@@ -0,0 +1,17 @@
+#pragma once
+
+namespace a8
+{
+    class Results
+    {
+    public:
+
+        Results(std::vector<std::any> results):results_(std::move(results)) {};
+
+        template <typename T>
+        T Get(size_t index) const { return std::any_cast<T>(results_.at(index));};
+
+    private:
+        std::vector<std::any> results_;
+    };
+}