public default void sideEffects(final String sideEffectKey, final Object sideEffectValue) throws IllegalArgumentException {
        this.asAdmin().getSideEffects().add(sideEffectKey, sideEffectValue);
    }
Add a particular value to the respective side-effect of the traverser (thus, traversal).

@param sideEffectKey   the key of the value to set int the sideEffects
@param sideEffectValue the value to set for the sideEffect key
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/Traverser.java