core/play/src/main/java/play/mvc/RangeResults.java
public static Result ofFile(Http.Request request, File file, String fileName) {
    return ofFile(request, file, fileName, StaticFileMimeTypes.fileMimeTypes());
  }
public static Result ofFile(Http.Request request, File file, String fileName) {
    return ofFile(request, file, fileName, StaticFileMimeTypes.fileMimeTypes());
  }
Returns the file as a result considering "Range" header. If the header is present and it is
satisfiable, then a Result containing just the requested part will be returned. If the header
is not present or is unsatisfiable, then a regular Result will be returned.

@param request the request from which to retrieve the range header.
@param file the content file
@param fileName filename used at the Content-Disposition header
@return range result if "Range" header is present and regular result if not