@Override
  public double getFlushPressure() {
    if (getRegionServerAccounting() == null || cacheFlusher == null) {
      // return 0 during RS initialization
      return 0.0;
    }
    return getRegionServerAccounting().getFlushPressure();
  }
For testing
@return whether all wal roll request finished for this regionserver
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java