diff --git a/src/Flecs.NET.Codegen/Helpers/Type.cs b/src/Flecs.NET.Codegen/Helpers/Type.cs
index 8fdf9a5..ae9d0bc 100644
--- a/src/Flecs.NET.Codegen/Helpers/Type.cs
+++ b/src/Flecs.NET.Codegen/Helpers/Type.cs
@@ -1,4 +1,3 @@
-
 using System.Diagnostics.CodeAnalysis;
 
 namespace Flecs.NET.Codegen.Helpers;
diff --git a/src/Flecs.NET/Core/BindingContext/Functions.cs b/src/Flecs.NET/Core/BindingContext/Functions.cs
index 586218a..0656a51 100644
--- a/src/Flecs.NET/Core/BindingContext/Functions.cs
+++ b/src/Flecs.NET/Core/BindingContext/Functions.cs
@@ -12,48 +12,54 @@ namespace Flecs.NET.Core.BindingContext;
 /// </summary>
 internal static unsafe class Functions
 {
-    #region  Context Free
+    #region Context Free
 
     [UnmanagedCallersOnly]
     internal static void WorldContextFree(WorldContext* context)
     {
-        context->Dispose();
-        Memory.Free(context);
+        WorldContext.Free(context);
     }
 
     [UnmanagedCallersOnly]
     internal static void IteratorContextFree(IteratorContext* context)
     {
-        context->Dispose();
-        Memory.Free(context);
+        IteratorContext.Free(context);
     }
 
     [UnmanagedCallersOnly]
     internal static void RunContextFree(RunContext* context)
     {
-        context->Dispose();
-        Memory.Free(context);
+        RunContext.Free(context);
     }
 
     [UnmanagedCallersOnly]
     internal static void QueryContextFree(QueryContext* context)
     {
-        context->Dispose();
-        Memory.Free(context);
+        QueryContext.Free(context);
     }
 
     [UnmanagedCallersOnly]
     internal static void GroupByContextFree(GroupByContext* context)
     {
-        context->Dispose();
-        Memory.Free(context);
+        GroupByContext.Free(context);
+    }
+
+    [UnmanagedCallersOnly]
+    internal static void SystemContextFree(SystemContext* context)
+    {
+        SystemContext.Free(context);
+    }
+
+    [UnmanagedCallersOnly]
+    internal static void ObserverContextFree(ObserverContext* context)
+    {
+        ObserverContext.Free(context);
     }
 
     [UnmanagedCallersOnly]
     internal static void TypeHooksContextFree(TypeHooksContext* context)
     {
-        context->Dispose();
-        Memory.Free(context);
+        TypeHooksContext.Free(context);
     }
 
     internal static void UserContextFinishDelegate<T>(ref UserContext context)
diff --git a/src/Flecs.NET/Core/BindingContext/GroupByContext.cs b/src/Flecs.NET/Core/BindingContext/GroupByContext.cs
index b8a78d7..4673a36 100644
--- a/src/Flecs.NET/Core/BindingContext/GroupByContext.cs
+++ b/src/Flecs.NET/Core/BindingContext/GroupByContext.cs
@@ -1,8 +1,9 @@
 using System;
+using Flecs.NET.Utilities;
 
 namespace Flecs.NET.Core.BindingContext;
 
-internal struct GroupByContext : IDisposable
+internal unsafe struct GroupByContext : IDisposable
 {
     public Callback GroupBy;
     public Callback GroupCreate;
@@ -16,4 +17,18 @@ public void Dispose()
         GroupDelete.Dispose();
         GroupByUserContext.Dispose();
     }
+
+    public static void Free(GroupByContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref GroupByContext context)
+    {
+        fixed (GroupByContext* ptr = &context)
+            Free(ptr);
+    }
 }
diff --git a/src/Flecs.NET/Core/BindingContext/IteratorContext.cs b/src/Flecs.NET/Core/BindingContext/IteratorContext.cs
index 3c0b246..9a79289 100644
--- a/src/Flecs.NET/Core/BindingContext/IteratorContext.cs
+++ b/src/Flecs.NET/Core/BindingContext/IteratorContext.cs
@@ -1,8 +1,9 @@
 using System;
+using Flecs.NET.Utilities;
 
 namespace Flecs.NET.Core.BindingContext;
 
-internal struct IteratorContext : IDisposable
+internal unsafe struct IteratorContext : IDisposable
 {
     public Callback Callback;
 
@@ -10,4 +11,18 @@ public void Dispose()
     {
         Callback.Dispose();
     }
+
+    public static void Free(IteratorContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref IteratorContext context)
+    {
+        fixed (IteratorContext* ptr = &context)
+            Free(ptr);
+    }
 }
diff --git a/src/Flecs.NET/Core/BindingContext/ObserverContext.cs b/src/Flecs.NET/Core/BindingContext/ObserverContext.cs
new file mode 100644
index 0000000..7e4742d
--- /dev/null
+++ b/src/Flecs.NET/Core/BindingContext/ObserverContext.cs
@@ -0,0 +1,28 @@
+using System;
+using Flecs.NET.Utilities;
+
+namespace Flecs.NET.Core.BindingContext;
+
+internal unsafe struct ObserverContext : IDisposable
+{
+    public UserContext UserContext;
+
+    public void Dispose()
+    {
+        UserContext.Dispose();
+    }
+
+    public static void Free(ObserverContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref ObserverContext context)
+    {
+        fixed (ObserverContext* ptr = &context)
+            Free(ptr);
+    }
+}
diff --git a/src/Flecs.NET/Core/BindingContext/OsApiContext.cs b/src/Flecs.NET/Core/BindingContext/OsApiContext.cs
index 05b62ee..3963332 100644
--- a/src/Flecs.NET/Core/BindingContext/OsApiContext.cs
+++ b/src/Flecs.NET/Core/BindingContext/OsApiContext.cs
@@ -1,8 +1,9 @@
 using System;
+using Flecs.NET.Utilities;
 
 namespace Flecs.NET.Core.BindingContext;
 
-internal struct OsApiContext : IDisposable
+internal unsafe struct OsApiContext : IDisposable
 {
     public Callback Abort;
     public Callback Log;
@@ -12,4 +13,18 @@ public void Dispose()
         Abort.Dispose();
         Log.Dispose();
     }
+
+    public static void Free(OsApiContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref OsApiContext context)
+    {
+        fixed (OsApiContext* ptr = &context)
+            Free(ptr);
+    }
 }
diff --git a/src/Flecs.NET/Core/BindingContext/Pointers.cs b/src/Flecs.NET/Core/BindingContext/Pointers.cs
index ffaf3b9..85f692c 100644
--- a/src/Flecs.NET/Core/BindingContext/Pointers.cs
+++ b/src/Flecs.NET/Core/BindingContext/Pointers.cs
@@ -33,6 +33,8 @@ static Pointers()
     internal static readonly nint RunContextFree = (nint)(delegate* unmanaged<RunContext*, void>)&Functions.RunContextFree;
     internal static readonly nint QueryContextFree = (nint)(delegate* unmanaged<QueryContext*, void>)&Functions.QueryContextFree;
     internal static readonly nint GroupByContextFree = (nint)(delegate* unmanaged<GroupByContext*, void>)&Functions.GroupByContextFree;
+    internal static readonly nint SystemContextFree = (nint)(delegate* unmanaged<SystemContext*, void>)&Functions.SystemContextFree;
+    internal static readonly nint ObserverContextFree = (nint)(delegate* unmanaged<ObserverContext*, void>)&Functions.ObserverContextFree;
     internal static readonly nint TypeHooksContextFree = (nint)(delegate* unmanaged<TypeHooksContext*, void>)&Functions.TypeHooksContextFree;
 
     #endregion
diff --git a/src/Flecs.NET/Core/BindingContext/PostFrameContext.cs b/src/Flecs.NET/Core/BindingContext/PostFrameContext.cs
index d28b295..574c668 100644
--- a/src/Flecs.NET/Core/BindingContext/PostFrameContext.cs
+++ b/src/Flecs.NET/Core/BindingContext/PostFrameContext.cs
@@ -1,8 +1,9 @@
 using System;
+using Flecs.NET.Utilities;
 
 namespace Flecs.NET.Core.BindingContext;
 
-internal struct PostFrameContext : IDisposable
+internal unsafe struct PostFrameContext : IDisposable
 {
     public Callback Callback;
 
@@ -10,4 +11,18 @@ public void Dispose()
     {
         Callback.Dispose();
     }
+
+    public static void Free(PostFrameContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref PostFrameContext context)
+    {
+        fixed (PostFrameContext* ptr = &context)
+            Free(ptr);
+    }
 }
diff --git a/src/Flecs.NET/Core/BindingContext/QueryContext.cs b/src/Flecs.NET/Core/BindingContext/QueryContext.cs
index 039cdaa..067e3b9 100644
--- a/src/Flecs.NET/Core/BindingContext/QueryContext.cs
+++ b/src/Flecs.NET/Core/BindingContext/QueryContext.cs
@@ -4,7 +4,7 @@
 
 namespace Flecs.NET.Core.BindingContext;
 
-internal struct QueryContext : IDisposable
+internal unsafe struct QueryContext : IDisposable
 {
     public Callback OrderBy;
     public Callback ContextFree;
@@ -24,4 +24,18 @@ public void Dispose()
 
         Strings.Dispose();
     }
+
+    public static void Free(QueryContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref QueryContext context)
+    {
+        fixed (QueryContext* ptr = &context)
+            Free(ptr);
+    }
 }
diff --git a/src/Flecs.NET/Core/BindingContext/RunContext.cs b/src/Flecs.NET/Core/BindingContext/RunContext.cs
index 34df7ed..fac5c52 100644
--- a/src/Flecs.NET/Core/BindingContext/RunContext.cs
+++ b/src/Flecs.NET/Core/BindingContext/RunContext.cs
@@ -1,8 +1,9 @@
 using System;
+using Flecs.NET.Utilities;
 
 namespace Flecs.NET.Core.BindingContext;
 
-internal struct RunContext : IDisposable
+internal unsafe struct RunContext : IDisposable
 {
     public Callback Callback;
 
@@ -10,4 +11,18 @@ public void Dispose()
     {
         Callback.Dispose();
     }
+
+    public static void Free(RunContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref RunContext context)
+    {
+        fixed (RunContext* ptr = &context)
+            Free(ptr);
+    }
 }
diff --git a/src/Flecs.NET/Core/BindingContext/SystemContext.cs b/src/Flecs.NET/Core/BindingContext/SystemContext.cs
new file mode 100644
index 0000000..89be70d
--- /dev/null
+++ b/src/Flecs.NET/Core/BindingContext/SystemContext.cs
@@ -0,0 +1,28 @@
+using System;
+using Flecs.NET.Utilities;
+
+namespace Flecs.NET.Core.BindingContext;
+
+internal unsafe struct SystemContext : IDisposable
+{
+    public UserContext UserContext;
+
+    public void Dispose()
+    {
+        UserContext.Dispose();
+    }
+
+    public static void Free(SystemContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref SystemContext context)
+    {
+        fixed (SystemContext* ptr = &context)
+            Free(ptr);
+    }
+}
diff --git a/src/Flecs.NET/Core/BindingContext/TypeHooksContext.cs b/src/Flecs.NET/Core/BindingContext/TypeHooksContext.cs
index 1415a65..3739ebe 100644
--- a/src/Flecs.NET/Core/BindingContext/TypeHooksContext.cs
+++ b/src/Flecs.NET/Core/BindingContext/TypeHooksContext.cs
@@ -1,8 +1,9 @@
 using System;
+using Flecs.NET.Utilities;
 
 namespace Flecs.NET.Core.BindingContext;
 
-internal struct TypeHooksContext : IDisposable
+internal unsafe struct TypeHooksContext : IDisposable
 {
     public int Header;
 
@@ -28,4 +29,18 @@ public void Dispose()
         OnRemove.Dispose();
         ContextFree.Dispose();
     }
+
+    public static void Free(TypeHooksContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref TypeHooksContext context)
+    {
+        fixed (TypeHooksContext* ptr = &context)
+            Free(ptr);
+    }
 }
diff --git a/src/Flecs.NET/Core/BindingContext/WorldContext.cs b/src/Flecs.NET/Core/BindingContext/WorldContext.cs
index a81f0a5..4c108cf 100644
--- a/src/Flecs.NET/Core/BindingContext/WorldContext.cs
+++ b/src/Flecs.NET/Core/BindingContext/WorldContext.cs
@@ -26,4 +26,18 @@ public void Dispose()
         foreach (nint ptr in WorldFinishContexts)
             Memory.Free((WorldFinishContext*)ptr);
     }
+
+    public static void Free(WorldContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref WorldContext context)
+    {
+        fixed (WorldContext* ptr = &context)
+            Free(ptr);
+    }
 }
diff --git a/src/Flecs.NET/Core/BindingContext/WorldFinishContext.cs b/src/Flecs.NET/Core/BindingContext/WorldFinishContext.cs
index 36420e6..ae9ff43 100644
--- a/src/Flecs.NET/Core/BindingContext/WorldFinishContext.cs
+++ b/src/Flecs.NET/Core/BindingContext/WorldFinishContext.cs
@@ -1,8 +1,9 @@
 using System;
+using Flecs.NET.Utilities;
 
 namespace Flecs.NET.Core.BindingContext;
 
-internal struct WorldFinishContext : IDisposable
+internal unsafe struct WorldFinishContext : IDisposable
 {
     public Callback Callback;
 
@@ -10,4 +11,18 @@ public void Dispose()
     {
         Callback.Dispose();
     }
+
+    public static void Free(WorldFinishContext* context)
+    {
+        if (context == null)
+            return;
+        context->Dispose();
+        Memory.Free(context);
+    }
+
+    public static void Free(ref WorldFinishContext context)
+    {
+        fixed (WorldFinishContext* ptr = &context)
+            Free(ptr);
+    }
 }
diff --git a/src/Flecs.NET/Core/ObserverBuilder.cs b/src/Flecs.NET/Core/ObserverBuilder.cs
index fa99379..27e962f 100644
--- a/src/Flecs.NET/Core/ObserverBuilder.cs
+++ b/src/Flecs.NET/Core/ObserverBuilder.cs
@@ -30,6 +30,10 @@ public unsafe partial struct ObserverBuilder : IDisposable, IEquatable<ObserverB
     /// </summary>
     public ref QueryBuilder QueryBuilder => ref _queryBuilder;
 
+    internal ref ObserverContext ObserverContext => ref *EnsureObserverContext();
+    internal ref IteratorContext IteratorContext => ref *EnsureIteratorContext();
+    internal ref RunContext RunContext => ref *EnsureRunContext();
+
     /// <summary>
     /// Creates an observer builder for the provided world.
     /// </summary>
@@ -66,8 +70,10 @@ public ObserverBuilder(ecs_world_t* world, string name) : this(world)
     public void Dispose()
     {
         QueryBuilder.Dispose();
-        FreeRun();
-        FreeCallback();
+        ObserverContext.Free(ref ObserverContext);
+        IteratorContext.Free(ref IteratorContext);
+        RunContext.Free(ref RunContext);
+        this = default;
     }
 
     /// <summary>
@@ -309,45 +315,25 @@ public Observer Each(delegate*<Iter, int, void> callback)
 
     internal ref ObserverBuilder SetCallback<T>(T callback, nint invoker) where T : Delegate
     {
-        FreeCallback();
-        IteratorContext context = default;
-        context.Callback.Set(callback, invoker);
-        Desc.callback = Pointers.IteratorCallback;
-        Desc.callback_ctx = Memory.Alloc(context);
-        Desc.callback_ctx_free = Pointers.IteratorContextFree;
+        IteratorContext.Callback.Set(callback, invoker);
         return ref this;
     }
 
     internal ref ObserverBuilder SetCallback(nint callback, nint invoker)
     {
-        FreeCallback();
-        IteratorContext context = default;
-        context.Callback.Set(callback, invoker);
-        Desc.callback = Pointers.IteratorCallback;
-        Desc.callback_ctx = Memory.Alloc(context);
-        Desc.callback_ctx_free = Pointers.IteratorContextFree;
+        IteratorContext.Callback.Set(callback, invoker);
         return ref this;
     }
 
     internal ref ObserverBuilder SetRun<T>(T callback, nint invoker) where T : Delegate
     {
-        FreeRun();
-        RunContext context = default;
-        context.Callback.Set(callback, invoker);
-        Desc.run = Pointers.RunCallback;
-        Desc.run_ctx = Memory.Alloc(context);
-        Desc.run_ctx_free = Pointers.RunContextFree;
+        RunContext.Callback.Set(callback, invoker);
         return ref this;
     }
 
     internal ref ObserverBuilder SetRun(nint callback, nint invoker)
     {
-        FreeRun();
-        RunContext context = default;
-        context.Callback.Set(callback, invoker);
-        Desc.run = Pointers.RunCallback;
-        Desc.run_ctx = Memory.Alloc(context);
-        Desc.run_ctx_free = Pointers.RunContextFree;
+        RunContext.Callback.Set(callback, invoker);
         return ref this;
     }
 
@@ -368,20 +354,36 @@ Observer IQueryBuilder<ObserverBuilder, Observer>.Build()
         return Build();
     }
 
-    private void FreeRun()
+    private ObserverContext* EnsureObserverContext()
     {
-        if (Desc.run == default)
-            return;
+        if (Desc.ctx != null)
+            return (ObserverContext*)Desc.ctx;
 
-        ((delegate*<void*, void>)Desc.run_ctx_free)(Desc.run_ctx);
+        Desc.ctx = Memory.AllocZeroed<ObserverContext>(1);
+        Desc.ctx_free = Pointers.ObserverContextFree;
+        return (ObserverContext*)Desc.ctx;
     }
 
-    private void FreeCallback()
+    private IteratorContext* EnsureIteratorContext()
     {
-        if (Desc.callback == default)
-            return;
+        if (Desc.callback_ctx != null)
+            return (IteratorContext*)Desc.callback_ctx;
 
-        ((delegate*<void*, void>)Desc.callback_ctx_free)(Desc.callback_ctx);
+        Desc.callback = Pointers.IteratorCallback;
+        Desc.callback_ctx = Memory.AllocZeroed<IteratorContext>(1);
+        Desc.callback_ctx_free = Pointers.IteratorContextFree;
+        return (IteratorContext*)Desc.callback_ctx;
+    }
+
+    private RunContext* EnsureRunContext()
+    {
+        if (Desc.run_ctx != null)
+            return (RunContext*)Desc.run_ctx;
+
+        Desc.run = Pointers.RunCallback;
+        Desc.run_ctx = Memory.AllocZeroed<RunContext>(1);
+        Desc.run_ctx_free = Pointers.RunContextFree;
+        return (RunContext*)Desc.run_ctx;
     }
 
     /// <summary>
diff --git a/src/Flecs.NET/Core/QueryBuilder.cs b/src/Flecs.NET/Core/QueryBuilder.cs
index 1e6650e..c4843d9 100644
--- a/src/Flecs.NET/Core/QueryBuilder.cs
+++ b/src/Flecs.NET/Core/QueryBuilder.cs
@@ -102,7 +102,9 @@ public QueryBuilder(ecs_world_t* world, string name) : this(world)
     /// </summary>
     public void Dispose()
     {
-        QueryContext.Dispose();
+        QueryContext.Free(ref QueryContext);
+        GroupByContext.Free(ref GroupByContext);
+        this = default;
     }
 
     /// <summary>
diff --git a/src/Flecs.NET/Core/SystemBuilder.cs b/src/Flecs.NET/Core/SystemBuilder.cs
index 2a72d84..21f44c1 100644
--- a/src/Flecs.NET/Core/SystemBuilder.cs
+++ b/src/Flecs.NET/Core/SystemBuilder.cs
@@ -29,6 +29,10 @@ public unsafe partial struct SystemBuilder : IDisposable, IEquatable<SystemBuild
     /// </summary>
     public ref QueryBuilder QueryBuilder => ref _queryBuilder;
 
+    internal ref SystemContext SystemContext => ref *EnsureSystemContext();
+    internal ref IteratorContext IteratorContext => ref *EnsureIteratorContext();
+    internal ref RunContext RunContext => ref *EnsureRunContext();
+
     /// <summary>
     ///     Creates a system builder for the provided world.
     /// </summary>
@@ -75,8 +79,10 @@ public SystemBuilder(ecs_world_t* world, string name)
     public void Dispose()
     {
         QueryBuilder.Dispose();
-        FreeRun();
-        FreeCallback();
+        SystemContext.Free(ref SystemContext);
+        IteratorContext.Free(ref IteratorContext);
+        RunContext.Free(ref RunContext);
+        this = default;
     }
 
     /// <summary>
@@ -396,46 +402,25 @@ public System_ Each(delegate*<Iter, int, void> callback)
 
     internal ref SystemBuilder SetCallback<T>(T callback, nint invoker) where T : Delegate
     {
-        FreeCallback();
-        IteratorContext context = default;
-        context.Callback.Set(callback, invoker);
-        Desc.callback = Pointers.IteratorCallback;
-        Desc.callback_ctx = Memory.Alloc(context);
-        Desc.callback_ctx_free = Pointers.IteratorContextFree;
+        IteratorContext.Callback.Set(callback, invoker);
         return ref this;
     }
 
     internal ref SystemBuilder SetCallback(nint callback, nint invoker)
     {
-        FreeCallback();
-        IteratorContext context = default;
-        context.Callback.Set(callback, invoker);
-        Desc.callback = Pointers.IteratorCallback;
-        Desc.callback_ctx = Memory.Alloc(context);
-        Desc.callback_ctx_free = Pointers.IteratorContextFree;
-
+        IteratorContext.Callback.Set(callback, invoker);
         return ref this;
     }
 
     internal ref SystemBuilder SetRun<T>(T callback, nint invoker) where T : Delegate
     {
-        FreeRun();
-        RunContext context = default;
-        context.Callback.Set(callback, invoker);
-        Desc.run = Pointers.RunCallback;
-        Desc.run_ctx = Memory.Alloc(context);
-        Desc.run_ctx_free = Pointers.RunContextFree;
+        RunContext.Callback.Set(callback, invoker);
         return ref this;
     }
 
     internal ref SystemBuilder SetRun(nint callback, nint invoker)
     {
-        FreeRun();
-        RunContext context = default;
-        context.Callback.Set(callback, invoker);
-        Desc.run = Pointers.RunCallback;
-        Desc.run_ctx = Memory.Alloc(context);
-        Desc.run_ctx_free = Pointers.RunContextFree;
+        RunContext.Callback.Set(callback, invoker);
         return ref this;
     }
 
@@ -452,20 +437,36 @@ System_ IQueryBuilder<SystemBuilder, System_>.Build()
         return Build();
     }
 
-    private void FreeRun()
+    private SystemContext* EnsureSystemContext()
     {
-        if (Desc.run == default)
-            return;
+        if (Desc.ctx != null)
+            return (SystemContext*)Desc.ctx;
 
-        ((delegate*<void*, void>)Desc.run_ctx_free)(Desc.run_ctx);
+        Desc.ctx = Memory.AllocZeroed<SystemContext>(1);
+        Desc.ctx_free = Pointers.SystemContextFree;
+        return (SystemContext*)Desc.ctx;
     }
 
-    private void FreeCallback()
+    private IteratorContext* EnsureIteratorContext()
     {
-        if (Desc.callback == default)
-            return;
+        if (Desc.callback_ctx != null)
+            return (IteratorContext*)Desc.callback_ctx;
+
+        Desc.callback = Pointers.IteratorCallback;
+        Desc.callback_ctx = Memory.AllocZeroed<IteratorContext>(1);
+        Desc.callback_ctx_free = Pointers.IteratorContextFree;
+        return (IteratorContext*)Desc.callback_ctx;
+    }
 
-        ((delegate*<void*, void>)Desc.callback_ctx_free)(Desc.callback_ctx);
+    private RunContext* EnsureRunContext()
+    {
+        if (Desc.run_ctx != null)
+            return (RunContext*)Desc.run_ctx;
+
+        Desc.run = Pointers.RunCallback;
+        Desc.run_ctx = Memory.AllocZeroed<RunContext>(1);
+        Desc.run_ctx_free = Pointers.RunContextFree;
+        return (RunContext*)Desc.run_ctx;
     }
 
     /// <summary>