@Override
  public long getRpcTimeout(TimeUnit unit) {
    return rawTable.getRpcTimeout(unit);
  }
Just a wrapper of {@link RawAsyncTableImpl}. The difference is that users need to provide a
thread pool when constructing this class, and the callback methods registered to the returned
{@link CompletableFuture} will be executed in this thread pool. So usually it is safe for users
to do anything they want in the callbacks without breaking the rpc framework.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncTableImpl.java