code: public static String getHeaderSegmentName(String segmentName) {
          Preconditions.checkArgument(!segmentName.endsWith(HEADER_SUFFIX), "segmentName is already a segment header name");
          return segmentName + HEADER_SUFFIX;
      }
docs: Gets the name of the meta-Segment mapped to the given Segment Name that is responsible with storing its Rollover
  information.
  Existence of this file should also indicate that a Segment with this file has a rollover policy in place.
  
  @param segmentName The name of the Segment to get the Header segment name for.
  @return The result.