@Override
    public String decideGroup(Event event) {
        StringBuilder stringBuilder = new StringBuilder("");
        dynamicTransportOptions
                .forEach(transportOption -> stringBuilder.append(transportOption.getValue(event))
                        .append(SiddhiConstants.KEY_DELIMITER));
        return stringBuilder.toString();
    }
Deciding the group of a given event and returning a unique identifier to identify the group. A correct
implementation of this method
should be returning  the same group identifier for all events belongs a give group.

@param event Event that needs to be decided to which group it belongs to
@return Unique Identifier to identify the group of the event
modules/siddhi-core/src/main/java/io/siddhi/core/stream/output/sink/DynamicOptionGroupDeterminer.java