public String getTimezone() {
        return timezone;
    }
Return the timezone as reported by the client, or null if the timezone
is not set.  Valid timezones are specified in IANA zone key format,
also known as Olson time zone database or TZ Database.

@return
    A string value of the timezone reported by the client.
guacamole-common/src/main/java/org/apache/guacamole/protocol/GuacamoleClientInformation.java