local math_min = math.min;
local xpcall, tostring, type = xpcall, tostring, type;
local traceback = debug.traceback;
+local runner = require"util.async".runner;
+local nameprep = require "util.encodings".stringprep.nameprep;
local xmlns_streams = "http://etherx.jabber.org/streams";
local xmlns_xmpp_streams = "urn:ietf:params:xml:ns:xmpp-streams";