@Override
  public CompletableFuture<Boolean> mergeSwitch(boolean enabled, boolean drainMerges) {
    return setSplitOrMergeOn(enabled, drainMerges, MasterSwitchType.MERGE);
  }
Compact the region at specific region server.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java