# Return self as a C hexadecimal digest where bytes are prefixed by `\x`
	#
	# The output is compatible with literal stream of bytes for most languages
	# including C and Nit.
	#
	# ~~~
	# var b = "abcd".to_bytes
	# assert b.chexdigest == "\\x61\\x62\\x63\\x64"
	# assert b.chexdigest.unescape_to_bytes == b
	# ~~~
	fun chexdigest: String do
		var elen = length * 4
		var ns = new CString(elen)
		var i = 0
		var oi = 0
		while i < length do
			ns[oi] = u'\\'
			ns[oi+1] = u'x'
			self[i].add_digest_at(ns, oi+2)
			i += 1
			oi += 4
		end
		return new FlatString.full(ns, elen, 0, elen)
	end