private void addParametersToConfiguration(final Graph graph) {
        parameters.getRaw(IO.writer, IO.writer, IO.registry).entrySet().forEach(kv -> {
            if (kv.getValue().size() == 1)
                graph.configuration().setProperty(kv.getKey().toString(), kv.getValue().get(0));
            else {
                // reset the default configuration with the first option then add to that for List options
                for (int ix = 0; ix < kv.getValue().size(); ix++) {
                    if (ix == 0)
                        graph.configuration().setProperty(kv.getKey().toString(), kv.getValue().get(ix));
                    else
                        graph.configuration().addProperty(kv.getKey().toString(), kv.getValue().get(ix));
                }
            }
        });
    }
Overwrites all configurations from values passed using {@link GraphTraversal#with(String, Object)}.
hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/process/computer/traversal/step/sideEffect/HadoopIoStep.java