wabbajack/Wabbajack.Common/ByteArrayExtensions.cs

using System;
using System.Collections.Generic;
using System.Linq;

namespace Wabbajack.Common
{
    public static class ByteArrayExtensions
    {
        public static byte[] ConcatArrays(this IReadOnlyCollection<byte[]> arrays)
        {
            var outArray = new byte[arrays.Sum(a => a.Length)];
            var offset = 0;
            foreach (var arr in arrays)
            {
                Array.Copy(arr, 0, outArray, offset, arr.Length);
                offset += arr.Length;
            }

            return outArray;
        }
    }
}