@Override
    public String toString() {
        return StringFactory.stepString(this, file, this.parameters);
    }
Builds a {@link GraphWriter} instance to use. Attempts to detect the file format to be write using the file
extension or simply uses configurations provided by the user on the parameters given to the step.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/sideEffect/IoStep.java