CommonHelpers: Add TimedValue helper

CommonHelpers/TimedValue.cs

@@ -0,0 +1,40 @@
+namespace CommonHelpers
+{
+    public class TimedValue<T> where T : struct
+    {
+        public T Value { get; }
+        public DateTime ExpiryDate { get; }
+
+        public bool Valid
+        {
+            get => !Expired;
+        }
+
+        public bool Expired
+        {
+            get => ExpiryDate < DateTime.UtcNow;
+        }
+
+        public TimedValue(T value, TimeSpan ts)
+        {
+            this.Value = value;
+            this.ExpiryDate = DateTime.UtcNow.Add(ts);
+        }
+
+        public TimedValue(T value, int timeoutMs)
+            : this(value, TimeSpan.FromMilliseconds(timeoutMs))
+        {
+        }
+
+        public bool TryGetValue(out T value)
+        {
+            value = this.Value;
+            return Valid;
+        }
+
+        public static implicit operator T?(TimedValue<T> tv)
+        {
+            return tv.Valid ? tv.Value : null;
+        }
+    }
+}