code: public void setStepDelayTo(String stepDelay) {
  		if ("slow".equals(stepDelay)) {
  			this.stepDelay = 1000;
  		} else if ("fast".equals(stepDelay)) {
  			this.stepDelay = 0;
  		} else {
  			this.stepDelay = Long.parseLong(stepDelay);
  		}
  	}
docs: <p>Set delay between steps.</p>
  <p><code>
  | set step delay to | 500 |
  | set step delay to | slow |
  | set step delay to | fast |
  </code></p>
  
  @param stepDelay delay in milliseconds