* port background threads setters
Signed-off-by: tabokie <xy.tao@outlook.com>

* format and fix build
Signed-off-by: tabokie <xy.tao@outlook.com>

* fix build
Signed-off-by: tabokie <xy.tao@outlook.com>

* fix test
Signed-off-by: tabokie <xy.tao@outlook.com>

* fix test
Signed-off-by: tabokie <xy.tao@outlook.com>

* fix test
Signed-off-by: tabokie <xy.tao@outlook.com>

* switch to i32
Signed-off-by: tabokie <xy.tao@outlook.com>

* format
Signed-off-by: tabokie <xy.tao@outlook.com>