local part length limit

[ysunICANN]

When you check the local part max length, your code include "@" which should not, so the following email failed (64 characters for the local part) because of RFC5321_LOCALPART_TOO_LONG warning.

64equalrtyuiopaasdfghjklzxcavbnmqwertyuiopasdfghjklzxcvbnmqwertd@test.com