@Override
  public CompletableFuture<Void> flushRegion(byte[] regionName) {
    return flushRegionInternal(regionName, null, false).thenAccept(r -> {
    });
  }
Utility for completing passed TableState {@link CompletableFuture} <code>future</code> using
passed parameters. Sets error or boolean result ('true' if table matches the passed-in
targetState).
hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java