default CompletableFuture<Boolean> balancerSwitch(boolean on) {
    return balancerSwitch(on, false);
  }
Turn the load balancer on or off.
@param on Set to <code>true</code> to enable, <code>false</code> to disable.
@return Previous balancer value wrapped by a {@link CompletableFuture}.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java