public void TestAllKeys()
        {
            var requestHeaders = new CosmosResponseMessageHeaders();

            requestHeaders.CosmosMessageHeaders[Key] = Guid.NewGuid().ToString();
            Assert.AreEqual(Key, requestHeaders.AllKeys().First());
        }
        public void TestAllKeysWithKnownProperties()
        {
            var requestHeaders = new CosmosResponseMessageHeaders();

            requestHeaders.CosmosMessageHeaders[Key] = Guid.NewGuid().ToString();
            requestHeaders.Continuation = Guid.NewGuid().ToString();
            requestHeaders.CosmosMessageHeaders[HttpConstants.HttpHeaders.RetryAfterInMilliseconds] = "20";
            requestHeaders.Add(WFConstants.BackendHeaders.SubStatus, "1002");
            var allKeys = requestHeaders.AllKeys();

            Assert.IsTrue(allKeys.Contains(Key));
            Assert.IsTrue(allKeys.Contains(HttpConstants.HttpHeaders.RetryAfterInMilliseconds));
            Assert.IsTrue(allKeys.Contains(HttpConstants.HttpHeaders.Continuation));
            Assert.IsTrue(allKeys.Contains(WFConstants.BackendHeaders.SubStatus));
        }