ByteReader.cs

void Main()
{
	var bytes = new byte[] { 0, 0, 1, 0, 255, 64 };
	var reader = new ByteReader(bytes);

	reader.Read<int>().Dump();
	reader.Read<byte>().Dump();
	reader.Read<sbyte>().Dump();
	reader.Read<byte>(4).Dump();
}

public unsafe class ByteReader
{
	private readonly byte[] _bytes;
	public uint Position { get; private set; } = 0;

	public ByteReader(byte[] bytes)
	{
		if (bytes == null)
		{
			throw new ArgumentNullException(nameof(bytes));
		}

		_bytes = bytes;
	}

	// Move position by size of T
	public void Move<T>()
		where T : struct
		=> Position += ((uint)Unsafe.SizeOf<T>());

	// Read sequentially
	public T Read<T>()
		where T : struct
	{
		var value = Read<T>(Position);
		Move<T>();
		
		return value;
	}

	// Read bytes from the start position + offset
	public T Read<T>(uint offset)
		where T : struct
	{
		fixed (byte* b = &_bytes[0])
		{
			return Unsafe.Read<T>(b + offset);
		}
	}
}