public Optional<String> getRequestId() {
            return null == requestId ? Optional.empty() : Optional.of(requestId);
        }
Gets the value of the request identifier supplied using the {@link GraphTraversal#with(String, Object)} source step.
If there are multiple commands using this step, the last usage should represent the id returned here.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/jsr223/GremlinScriptChecker.java