code: @SuppressWarnings("WeakerAccess")
    public ApiFuture<Void> dropAllRowsAsync(String tableId) {
      DropRowRangeRequest request =
          DropRowRangeRequest.newBuilder()
              .setName(getTableName(tableId))
              .setDeleteAllDataFromTable(true)
              .build();
  
      return transformToVoid(this.stub.dropRowRangeCallable().futureCall(request));
    }
docs: Asynchornously drops all data in the table.
  
  <p>Sample code:
  
  <pre>{@code
  ApiFuture<Void> dropFuture = client.dropAllRowsAsync("my-table");
  
  ApiFutures.addCallback(
  dropFuture,
  new ApiFutureCallback<Void>() {
  public void onSuccess(Void tableNames) {
  System.out.println("Successfully dropped all data");
  }
  
  public void onFailure(Throwable t) {
  t.printStackTrace();
  }
  },
  MoreExecutors.directExecutor()
  );
  }</pre>