BatchRendererGroup data layouting helper

InstanceDataLayouter.cs

using System;
using System.Runtime.CompilerServices;
using Unity.Collections;
using UnityEngine;
using UnityEngine.Rendering;

public struct InstanceDataLayouter
{
    private int _offset;
    private int _metadataIndex;

    public int NumMetadata => _metadataIndex;

    public InstanceDataInfo<T> Alloc<T>(int nameId, int count, ref NativeArray<T>? array) where T : unmanaged
    {
        var stride = Unsafe.SizeOf<T>();
        _offset = AlignTo(_offset, stride);

        if (array is not { } arrayValue || arrayValue.Length != count)
        {
            array?.Dispose();
            array = new NativeArray<T>(count, Allocator.Persistent);
        }

        var result =
            new InstanceDataInfo<T>(nameId, _offset / stride, _offset, _metadataIndex++, array.Value, false);

        _offset += count * stride;

        return result;
    }

    public InstanceDataInfo<T> AllocStatic<T>(int nameId, ref NativeArray<T>? array) where T : unmanaged
    {
        var stride = Unsafe.SizeOf<T>();
        _offset = AlignTo(_offset, stride);

        if (array is not { } arrayValue || arrayValue.Length != 1)
        {
            array?.Dispose();
            array = new NativeArray<T>(1, Allocator.Persistent);
        }

        var result =
            new InstanceDataInfo<T>(nameId, _offset / stride, _offset, _metadataIndex++, array.Value, true);

        _offset += stride;

        return result;
    }

    public void AllocZero<T>(int count) where T : unmanaged
    {
        var stride = Unsafe.SizeOf<T>();
        _offset = AlignTo(_offset, stride);

        _offset += count * stride;
    }

    static int AlignTo(int offset, int stride) => (offset + stride - 1) / stride * stride;

    public int GetSize(int alignment)
    {
        return AlignTo(_offset, alignment);
    }
}

public struct InstanceDataInfo<T> where T : unmanaged
{
    private readonly int? _nameId;
    private readonly int _graphicsBufferStartIndex;
    private readonly int _offset;
    private readonly int _metadataIndex;
    private readonly bool _isStatic;
    public NativeArray<T> Array;

    public InstanceDataInfo(int? nameId, int graphicsBufferStartIndex, int offset, int metadataIndex,
        NativeArray<T> array, bool isStatic)
    {
        _nameId = nameId;
        _graphicsBufferStartIndex = graphicsBufferStartIndex;
        _offset = offset;
        _metadataIndex = metadataIndex;
        _isStatic = isStatic;
        Array = array;
    }

    public void ApplyMetadata(Span<MetadataValue> metadata)
    {
        if (_nameId is { } nameId)
        {
            metadata[_metadataIndex] = new MetadataValue()
            {
                NameID = nameId,
                Value = (uint)_offset | (_isStatic ? 0 : 0x80000000)
            };
        }
    }

    public void ApplyValue(GraphicsBuffer buffer)
    {
        buffer.SetData(Array, 0, _graphicsBufferStartIndex, Array.Length);
    }
}