private static Result toResult(HBaseRpcController controller, MutateResponse resp)
    throws IOException {
    if (!resp.hasResult()) {
      return null;
    }
    return ProtobufUtil.toResult(resp.getResult(), controller.cellScanner());
  }
The implementation of RawAsyncTable.
<p/>
The word 'Raw' means that this is a low level class. The returned {@link CompletableFuture} will
be finished inside the rpc framework thread, which means that the callbacks registered to the
{@link CompletableFuture} will also be executed inside the rpc framework thread. So users who use
this class should not try to do time consuming tasks in the callbacks.
@since 2.0.0
@see AsyncTableImpl
hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncTableImpl.java