private static void usage() {
    System.err.println("Usage: AbstractFSWAL <ARGS>");
    System.err.println("Arguments:");
    System.err.println(" --dump  Dump textual representation of passed one or more files");
    System.err.println("         For example: "
      + "AbstractFSWAL --dump hdfs://example.com:9000/hbase/WALs/MACHINE/LOGFILE");
    System.err.println(" --split Split the passed directory of WAL logs");
    System.err.println(
      "         For example: AbstractFSWAL --split hdfs://example.com:9000/hbase/WALs/DIR");
  }
Returns true if we exceeded the slow sync roll threshold over the last check interval
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/AbstractFSWAL.java