# Fire the appearance of an attribute.
	fun fire_attribute(qname: String, value: String) do
		if "xmlns" == qname or qname.has_prefix("xmlns:") then
			var prefix = qname.substring_from("xmlns:".length)

			if not prefix.has(":") then
				fire_start_prefix_mapping(prefix, value)
				if not feature(feature_namespace_prefixes_uri) then return
			end
		end
		# TODO: Types.
		atts.add("", "", qname, "CDATA", value)
	end