print a var instance GtidEvent，raise a TypeError in mysql 5.7.17.

print(debug_info(), idx, event)
var event is instanceof GtidEvent，occur Exception TypeError: ord() expected string of length 1, but int found.

gtid = "%s%s%s%s-%s%s-%s%s-%s%s-%s%s%s%s%s%s" %\
tuple("{0:02x}".format(ord(c)) for c in self.sid)
function ord() need type char, but var c is type int。

Start at GtidEvent's gtid formatting shown in the report, especially conversion of self.sid values, and reproduce the TypeError on MySQL 5.7.17. Done means the event can be printed without the ord() type error and the resulting GTID remains correctly formatted.

Written by the indexing model from the issue text.