static void ValidateArguments (byte[] buffer, int offset, int count)
{
if (buffer == null)
throw new ArgumentNullException (nameof (buffer));
if (offset < 0 || offset > buffer.Length)
throw new ArgumentOutOfRangeException (nameof (offset));
if (count < 0 || count > (buffer.Length - offset))
throw new ArgumentOutOfRangeException (nameof (count));
}