protected static void printUsage(final String message) {
    printUsage(PE_COMMAND_SHORTNAME, message);
  }
Compute a throughput rate in MB/s.
@param rows   Number of records consumed.
@param timeMs Time taken in milliseconds.
@return String value with label, ie '123.76 MB/s'
hbase-diagnostics/src/main/java/org/apache/hadoop/hbase/PerformanceEvaluation.java