Add overload in UniTask.WaitUntil, UniTask.WaitWhile and UniTask.Defer

src/UniTask/Assets/Plugins/UniTask/Runtime/UniTask.Factory.cs

@@ -202,6 +202,22 @@ public static UniTask<T> Defer<T>(Func<UniTask<T>> factory)
             return new UniTask<T>(new DeferPromise<T>(factory), 0);
         }
 
+        /// <summary>
+        /// Defer the task creation just before call await.
+        /// </summary>
+        public static UniTask Defer<TState>(TState state, Func<TState, UniTask> factory)
+        {
+            return new UniTask(new DeferPromiseWithState<TState>(state, factory), 0);
+        }
+
+        /// <summary>
+        /// Defer the task creation just before call await.
+        /// </summary>
+        public static UniTask<TResult> Defer<TState, TResult>(TState state, Func<TState, UniTask<TResult>> factory)
+        {
+            return new UniTask<TResult>(new DeferPromiseWithState<TState, TResult>(state, factory), 0);
+        }
+
         /// <summary>
         /// Never complete.
         /// </summary>
@@ -465,6 +481,93 @@ public UniTaskStatus UnsafeGetStatus()
             }
         }
 
+        sealed class DeferPromiseWithState<TState> : IUniTaskSource
+        {
+            Func<TState, UniTask> factory;
+            TState argument;
+            UniTask task;
+            UniTask.Awaiter awaiter;
+
+            public DeferPromiseWithState(TState argument, Func<TState, UniTask> factory)
+            {
+                this.argument = argument;
+                this.factory = factory;
+            }
+
+            public void GetResult(short token)
+            {
+                awaiter.GetResult();
+            }
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                var f = Interlocked.Exchange(ref factory, null);
+                if (f != null)
+                {
+                    task = f(argument);
+                    awaiter = task.GetAwaiter();
+                }
+
+                return task.Status;
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                awaiter.SourceOnCompleted(continuation, state);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return task.Status;
+            }
+        }
+
+        sealed class DeferPromiseWithState<TState, TResult> : IUniTaskSource<TResult>
+        {
+            Func<TState, UniTask<TResult>> factory;
+            TState argument;
+            UniTask<TResult> task;
+            UniTask<TResult>.Awaiter awaiter;
+
+            public DeferPromiseWithState(TState argument, Func<TState, UniTask<TResult>> factory)
+            {
+                this.argument = argument;
+                this.factory = factory;
+            }
+
+            public TResult GetResult(short token)
+            {
+                return awaiter.GetResult();
+            }
+
+            void IUniTaskSource.GetResult(short token)
+            {
+                awaiter.GetResult();
+            }
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                var f = Interlocked.Exchange(ref factory, null);
+                if (f != null)
+                {
+                    task = f(argument);
+                    awaiter = task.GetAwaiter();
+                }
+
+                return task.Status;
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                awaiter.SourceOnCompleted(continuation, state);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return task.Status;
+            }
+        }
+
         sealed class NeverPromise<T> : IUniTaskSource<T>
         {
             static readonly Action<object> cancellationCallback = CancellationCallback;