private static String toScannerName(long scannerId) {
    return Long.toString(scannerId);
  }
The returned String is used as key doing look up of outstanding Scanners in this Servers'
this.scanners, the Map of outstanding scanners and their current state.
@param scannerId A scanner long id.
@return The long id as a String.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java