/// <summary>
/// Reads eight-bytes unsigned value from the underlaying stream.
/// </summary>
/// <returns><see cref="ulong"/> read</returns>
/// <exception cref="IOException">Thrown when end of stream was reached and <see cref="Unsecure"/> is false.</exception>
public ulong ReadULong()
{
AssertRead(8, "ULong");
return(BE ? ByteUtils.ToULongBE(buffer) : ByteUtils.ToULongLE(buffer));
}