From 75223a315dc81c6d81256aae9a05ac6a265358a8 Mon Sep 17 00:00:00 2001
From: Valentin Kononov <valentin.kononov@gmail.com>
Date: Sat, 19 May 2018 09:54:21 +0300
Subject: [PATCH] feat(QueryFutureEnumerable) : add FirstOrDefaultAsync
 implementation

---
 .../QueryFutureEnumerable.cs                  | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/shared/Z.EF.Plus.QueryFuture.Shared/QueryFutureEnumerable.cs b/src/shared/Z.EF.Plus.QueryFuture.Shared/QueryFutureEnumerable.cs
index e1cba051..497c73b3 100644
--- a/src/shared/Z.EF.Plus.QueryFuture.Shared/QueryFutureEnumerable.cs
+++ b/src/shared/Z.EF.Plus.QueryFuture.Shared/QueryFutureEnumerable.cs
@@ -121,6 +121,25 @@ public async Task<T[]> ToArrayAsync()
                 return list.ToArray();
             }
         }
+
+        public async Task<T> FirstOrDefaultAsync()
+        {
+            if (!HasValue)
+            {
+                await OwnerBatch.ExecuteQueriesAsync().ConfigureAwait(false);
+            }
+
+            if (_result == null)
+            {
+                return default(T);
+            }
+
+            using (var enumerator = _result.GetEnumerator())
+            {
+                enumerator.MoveNext();
+                return enumerator.Current;
+            }
+        }
 #endif
 
         /// <summary>Sets the result of the query deferred.</summary>