fix: Unity 2020 support

Assets/Mirror/Core/NetworkConnection.cs

@@ -178,14 +178,15 @@ internal virtual void Send(ArraySegment<byte> segment, int channelId = Channels.
         internal virtual void Update()
         {
             // go through batches for all channels
-            foreach ((int key, Batcher batcher) in batches)
+            // foreach ((int key, Batcher batcher) in batches) // Unity 2020 doesn't support deconstruct yet
+            foreach (KeyValuePair<int, Batcher> kvp in batches)
             {
                 // make and send as many batches as necessary from the stored
                 // messages.
                 using (NetworkWriterPooled writer = NetworkWriterPool.Get())
                 {
                     // make a batch with our local time (double precision)
-                    while (batcher.GetBatch(writer))
+                    while (kvp.Value.GetBatch(writer))
                     {
                         // validate packet before handing the batch to the
                         // transport. this guarantees that we always stay
@@ -193,10 +194,10 @@ internal virtual void Update()
                         // => just in case transport forgets to check it
                         // => just in case mirror miscalulated it etc.
                         ArraySegment<byte> segment = writer.ToArraySegment();
-                        if (ValidatePacketSize(segment, key))
+                        if (ValidatePacketSize(segment, kvp.Key))
                         {
                             // send to transport
-                            SendToTransport(segment, key);
+                            SendToTransport(segment, kvp.Key);
                             //UnityEngine.Debug.Log($"sending batch of {writer.Position} bytes for channel={kvp.Key} connId={connectionId}");
 
                             // reset writer for each new batch

Assets/Mirror/Core/Tools/Vector3Long.cs

@@ -48,6 +48,9 @@ public Vector3Long(long x, long y, long z)
         public static Vector3Long operator *(long n, Vector3Long a) =>
             new Vector3Long(a.x * n, a.y * n, a.z * n);
 
+// Unity 2019/2020 don't have HashCode.Combine yet.
+// this is only to avoid reflection. without defining, it works too.
+#if UNITY_2021_3_OR_NEWER
         // == returns true if approximately equal (with epsilon).
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool operator ==(Vector3Long a, Vector3Long b) =>
@@ -57,6 +60,7 @@ public Vector3Long(long x, long y, long z)
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool operator !=(Vector3Long a, Vector3Long b) => !(a == b);
+#endif
 
         // NO IMPLICIT System.Numerics.Vector3Long conversion because double<->float
         // would silently lose precision in large worlds.
@@ -94,6 +98,9 @@ public long this[int index]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public override string ToString() => $"({x} {y} {z})";
 
+// Unity 2019/2020 don't have HashCode.Combine yet.
+// this is only to avoid reflection. without defining, it works too.
+#if UNITY_2021_3_OR_NEWER
         // equality ////////////////////////////////////////////////////////////
         // implement Equals & HashCode explicitly for performance.
         // calling .Equals (instead of "==") checks for exact equality.
@@ -110,5 +117,6 @@ public override bool Equals(object other) =>
         // default generated by rider
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public override int GetHashCode() => HashCode.Combine(x, y, z);
+#endif
     }
 }

Assets/Mirror/Tests/Editor/Vector3LongTests.cs

@@ -55,6 +55,7 @@ public void OperatorMultiply()
             Assert.That(2 * a, Is.EqualTo(new Vector3Long(2, 4, 6)));
         }
 
+#if UNITY_2021_3_OR_NEWER
         [Test]
         public void OperatorEquals()
         {
@@ -78,6 +79,7 @@ public void OperatorNotEquals()
             // two vectors which are definitely not the same
             Assert.That(a != Vector3Long.one, Is.True);
         }
+#endif
 
         [Test]
         public void OperatorIndexer()
@@ -114,6 +116,7 @@ public void ToStringTest()
             Assert.That(v.ToString(), Is.EqualTo("(-10 0 42)"));
         }
 
+#if UNITY_2021_3_OR_NEWER
         [Test]
         public void EqualsVector3Long()
         {
@@ -142,5 +145,6 @@ public void GetHashCodeTest()
             // should be different for different vectors
             Assert.That(Vector3Long.zero.GetHashCode(), !Is.EqualTo(Vector3Long.one.GetHashCode()));
         }
+#endif
     }
 }