enter intro cutscene

Common/Util/DateTime.cs

@@ -0,0 +1,14 @@
+
+namespace MikuSB.Util;
+
+
+public static class DateTimeExtensions
+{
+    private static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+
+    public static long ToUnixTimestampMilliseconds(this DateTime dateTime)
+    {
+        return (long)(dateTime - UnixEpoch).TotalMilliseconds;
+    }
+
+}