Implement handshake Hello NetControlMessage, recv and send

src/Prospect.Unreal/Core/FPlatformTime.cs

@@ -0,0 +1,9 @@
+namespace Prospect.Unreal.Core;
+
+public static class FPlatformTime
+{
+    public static double Seconds()
+    {
+        return DateTimeOffset.UtcNow.ToUnixTimeSeconds();
+    }
+}

src/Prospect.Unreal/Core/UObject.cs

@@ -0,0 +1,6 @@
+namespace Prospect.Unreal.Core;
+
+public class UObject
+{
+    
+}