code: public void reset() throws IOException {
  		if (t1==null || t2==null) {
  			throw new IllegalStateException("Cannot reset after close.");
  		}
  		if (!isEmpty(getOutput())) {
  			toggle = !toggle;
  			// reset the new output
  			PathTools.deleteRecursive(getOutput(), false);
  		} else {
  			throw new IOException("Cannot swap to an empty folder.");
  		}
  	}
docs: Resets the input and output folder before writing to the output again
  
  @throws IOException
  An IOException is thrown if TempFolderHandler has been
  closed or if the output folder is empty.