fix keyExpiry's DateTime convert to Utc

StackExchange.Redis.Tests/Expiry.cs

@@ -61,7 +61,7 @@ public void TestBasicExpiryDateTime(bool disablePTimes, bool utc)
                 var conn = muxer.GetDatabase();
                 conn.KeyDelete(key, CommandFlags.FireAndForget);
 
-                var now = utc ? DateTime.UtcNow : DateTime.Now;
+                var now = utc ? DateTime.UtcNow : new DateTime(DateTime.UtcNow.Ticks + TimeZoneInfo.FindSystemTimeZoneById("Tokyo Standard Time").BaseUtcOffset.Ticks, DateTimeKind.Local);
                 conn.StringSet(key, "new value", flags: CommandFlags.FireAndForget);
                 var a = conn.KeyTimeToLiveAsync(key);
                 conn.KeyExpire(key, now.AddHours(1), CommandFlags.FireAndForget);

StackExchange.Redis/StackExchange/Redis/RedisDatabase.cs

@@ -1602,7 +1602,7 @@ Message GetExpiryMessage(RedisKey key, CommandFlags flags, DateTime? expiry, out
                 default:
                     throw new ArgumentException("Expiry time must be either Utc or Local", "expiry");
             }
-            long milliseconds = (when - RedisBase.UnixEpoch).Ticks / TimeSpan.TicksPerMillisecond;
+            long milliseconds = (when.ToUniversalTime() - RedisBase.UnixEpoch).Ticks / TimeSpan.TicksPerMillisecond;
 
             if ((milliseconds % 1000) != 0)
             {