正在声明内部字典比较器C#

我有一个字典，如下

Dictionary<ulong, Dictionary<byte[], byte[]>> Info;

内部字典保存一个byte[]数组作为关键字。

我无法理解如何为Info字典声明构造函数。对于内部密钥比较，我有ByteArrayComparer、

  public class ByteArrayComparer : IEqualityComparer<byte[]> 
    {
        public bool Equals(byte[] left, byte[] right)
        {
            if (left == null || right == null)
            {
                return left == right;
            }
            if (left.Length != right.Length)
            {
                return false;
            }
            for (int i = 0; i < left.Length; i++)
            {
                if (left[i] != right[i])
                {
                    return false;
                }
            }
            return true;
        }
        public int GetHashCode(byte[] key)
        {
            if (key == null)
                throw new ArgumentNullException("key");
            int sum = 0;
            foreach (byte cur in key)
            {
                sum += cur;
            }
            return sum;
  }
}

我从SO Here 那里买的

请告知

// It's stateless, so let's just use one of them.
private static readonly IEqualityComparer<byte[]> ByteArrayComparerInstance
    = new ByteArrayComparer();
Dictionary<ulong, Dictionary<byte[], byte[]>> Info
    = new Dictionary<ulong, Dictionary<byte[], byte[]>();
....
...
Dictionary<byte[], byte[]> valueMap;
if (!Info.TryGetValue(key, out valueMap))
{
    valueMap = new Dictionary<byte[], byte[]>(ByteArrayComparerInstance);
    Info[key] = valueMap;
}
...