code: protected String createFile() throws IOException {
          generateNewBasename();
          String name = currentBasename + '.' + this.extension  +
              ((settings.getCompress())? DOT_COMPRESSED_FILE_EXTENSION: "") +
              OCCUPIED_SUFFIX;
          File dir = getNextDirectory(settings.calcOutputDirs());
          return createFile(new File(dir, name));
      }
docs: Create a new file.
  Rotates off the current Writer and creates a new in its place
  to take subsequent writes.  Usually called from {@link #checkSize()}.
  @return Name of file created.
  @throws IOException