public void setExpires(Long expires) {
        this.expires = expires;
    }
Sets the time after which the data stored in this object is invalid
and must not be used. The time provided MUST be a UNIX-style epoch
timestamp whose value is the number of milliseconds since midnight of
January 1, 1970 UTC. If this object should not expire, the value
provided should be null.

@param expires
    The time after which the data stored in this object is invalid and
    must not be used, or null if this object does not expire.
extensions/guacamole-auth-json/src/main/java/org/apache/guacamole/auth/json/user/UserData.java