# Trims off the whitespaces at the beginning and the end of `self`
	#
	#     var b = "102041426E6F1020" .hexdigest_to_bytes
	#     assert b.trim.hexdigest == "41426E6F"
	#
	# NOTE: A whitespace is defined here as a byte whose value is <= 0x20
	fun trim: Bytes do
		var st = 0
		while st < length do
			if self[st] > 0x20 then break
			st += 1
		end
		if st >= length then return new Bytes.empty
		var ed = length - 1
		while ed > 0 do
			if self[ed] > 0x20 then break
			ed -= 1
		end
		return slice(st, ed - st + 1)
	end