@Override
    public SparkGraphComputer configure(final String key, final Object value) {
        this.sparkConfiguration.setProperty(key, value);
        return this;
    }
Sets the number of workers. If the {@code spark.master} configuration is configured with "local" then it will
change that configuration to use the specified number of worker threads.
spark-gremlin/src/main/java/org/apache/tinkerpop/gremlin/spark/process/computer/SparkGraphComputer.java