fix: fixing time packing returning negative values

Assets/NetworkPositionSync/Runtime/SyncSettings.cs

@@ -172,14 +172,14 @@ public VarDoublePacker(double precision, int blockSize)
 
             public void Pack(NetworkWriter writer, double value)
             {
-                var scaled = (int)Math.Round(value * _inversePrecision);
+                var scaled = (long)Math.Round(value * _inversePrecision);
                 var zig = ZigZag.Encode(scaled);
                 VarIntBlocksPacker.Pack(writer, zig, _blockSize);
             }
 
             public double Unpack(NetworkReader reader)
             {
-                var zig = (uint)VarIntBlocksPacker.Unpack(reader, _blockSize);
+                var zig = VarIntBlocksPacker.Unpack(reader, _blockSize);
                 var scaled = ZigZag.Decode(zig);
                 return scaled * _precision;
             }

Assets/NetworkPositionSync/Tests/Runtime/TimeSyncTest.cs

@@ -0,0 +1,29 @@
+using Mirage.Serialization;
+using NUnit.Framework;
+using UnityEngine;
+
+namespace JamesFrowen.PositionSync.Tests
+{
+    [Category("NetworkPositionSync")]
+    public class TimeSyncTest : MonoBehaviour
+    {
+        [Test]
+        public void TimeSerialzesCorrectly([NUnit.Framework.Range(0, 3600 * 24 * 30, 1000)] double time)
+        {
+            var settings = new SyncSettings();
+            var writer = new NetworkWriter(1200);
+
+            var packer = settings.CreateTimePacker();
+
+            packer.Pack(writer, time);
+
+            var reader = new NetworkReader();
+            reader.Reset(writer.ToArraySegment());
+
+            var outTime = packer.Unpack(reader);
+
+            // setting should be sending 0.1ms, so should be within that
+            Assert.That(outTime, Is.EqualTo(time).Within(1 / 10000f));
+        }
+    }
+}