add new struct definitions

Il2CppInspector.Common/Next/Metadata/Il2CppEventDefinition.cs

@@ -0,0 +1,24 @@
+namespace Il2CppInspector.Next.Metadata;
+
+using StringIndex = int;
+using TypeIndex = int;
+using MethodIndex = int;
+using VersionedSerialization.Attributes;
+
+[VersionedStruct]
+public partial struct Il2CppEventDefinition
+{
+    public StringIndex NameIndex { get; private set; }
+    public TypeIndex TypeIndex { get; private set; }
+    public MethodIndex Add { get; private set; }
+    public MethodIndex Remove { get; private set; }
+    public MethodIndex Raise { get; private set; }
+
+    [VersionCondition(LessThan = "24.0")]
+    public int CustomAttributeIndex { get; private set; }
+
+    [VersionCondition(GreaterThan = "19.0")]
+    public uint Token { get; private set; }
+
+    public readonly bool IsValid => NameIndex != 0;
+}