--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Implab/PromiseAwaiter`1.cs	Tue Jan 30 01:37:17 2018 +0300
@@ -0,0 +1,62 @@
+using System;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using Implab.Parallels;
+
+namespace Implab {
+    public struct PromiseAwaiter<T> : INotifyCompletion {
+        class PromiseEvent : IResolvable<T> {
+            IDispatcher m_dispatcher;
+
+            Action m_handler;
+
+            public PromiseEvent(Action handler, IDispatcher dispatcher) {
+                m_handler = handler;
+                m_dispatcher = dispatcher;
+            }
+
+            public void Resolve(T result) {
+                m_dispatcher.Enqueue(m_handler);
+            }
+
+            public void Reject(Exception error) {
+                m_dispatcher.Enqueue(m_handler);
+            }
+        }
+
+        readonly IPromise<T> m_promise;
+
+        readonly IDispatcher m_dispatcher;
+
+        public PromiseAwaiter(IPromise<T> promise) {
+            m_promise = promise;
+            m_dispatcher = GetDispatcher();
+        }
+
+        public PromiseAwaiter(IPromise<T> promise, IDispatcher dispatcher) {
+            m_promise = promise;
+            m_dispatcher = dispatcher;
+        }
+
+        public void OnCompleted(Action continuation) {
+            if (m_promise != null)
+                m_promise.Then(new PromiseEvent(continuation, GetDispatcher()));
+        }
+
+        public T GetResult() {
+            return m_promise.Join();
+        }
+
+        static IDispatcher GetDispatcher() {
+            if (SynchronizationContext.Current == null)
+                return ThreadPoolDispatcher.Instance;
+            return new SyncContextDispatcher(SynchronizationContext.Current);
+        }
+
+        public bool IsCompleted {
+            get {
+                return m_promise.IsResolved;
+            }
+        }
+    }
+}
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