code: func SegmentEnd(id, segId int64) (int, error) {
  	return errNo(C.newrelic_segment_end(C.long(id), C.long(segId)))
  }
docs: /*
   * Identify the end of a segment
   *
   * @param transaction_id  id of transaction
   * @param egment_id  id of the segment to end
   * @return  0 on success, else negative warning code or error code
   */