perf: reduce networkbehaviourilpp type resolution time

[NoelStephensUnity]

User submitted PR: #3224

Measurement

With minimalproject, I used the following code for measurement.

diff --git a/com.unity.netcode.gameobjects/Editor/CodeGen/NetworkBehaviourILPP.cs b/com.unity.netcode.gameobjects/Editor/CodeGen/NetworkBehaviourILPP.cs
index 7e95fea9..39b4f991 100644
--- a/com.unity.netcode.gameobjects/Editor/CodeGen/NetworkBehaviourILPP.cs
+++ b/com.unity.netcode.gameobjects/Editor/CodeGen/NetworkBehaviourILPP.cs
@@ -77,6 +77,8 @@ namespace Unity.Netcode.Editor.CodeGen
 
             m_Diagnostics.Clear();
 
+            var sw = System.Diagnostics.Stopwatch.StartNew();
+
             // read
             var assemblyDefinition = CodeGenHelpers.AssemblyDefinitionFor(compiledAssembly, out m_AssemblyResolver);
             if (assemblyDefinition == null)
@@ -171,6 +173,8 @@ namespace Unity.Netcode.Editor.CodeGen
 
             assemblyDefinition.Write(pe, writerParameters);
 
+            m_Diagnostics.AddWarning($"ILPP has completed for {compiledAssembly.Name} in {sw.ElapsedMilliseconds} ms");
+
             return new ILPostProcessResult(new InMemoryAssembly(pe.ToArray(), pdb.ToArray()), m_Diagnostics);
         }
 

Before

(0,0): warning  - ILPP has completed for Unity.Netcode.Editor in 531 ms
(0,0): warning  - ILPP has completed for Unity.Netcode.EditorTests in 604 ms
(0,0): warning  - ILPP has completed for Unity.Netcode.Components in 363 ms
(0,0): warning  - ILPP has completed for Unity.Netcode.TestHelpers.Runtime in 330 ms
(0,0): warning  - ILPP has completed for Unity.Netcode.RuntimeTests in 735 ms

After

(0,0): warning  - ILPP has completed for Unity.Netcode.Editor in 79 ms
(0,0): warning  - ILPP has completed for Unity.Netcode.EditorTests in 128 ms
(0,0): warning  - ILPP has completed for Unity.Netcode.Components in 146 ms
(0,0): warning  - ILPP has completed for Unity.Netcode.TestHelpers.Runtime in 117 ms
(0,0): warning  - ILPP has completed for Unity.Netcode.RuntimeTests in 537 ms

Changelog

• Changed: Improved performance of NetworkBehaviour ILPostProcessor by omitting unnecessary type and assembly resolutions.

Testing and Documentation

• No tests have been added.
• No documentation changes or additions were necessary.