feat: add get field count method.
feat: add get field count method.

kenjis/CodeIgniter4,kenjis/CodeIgniter4,bcit-ci/CodeIgniter4,kenjis/CodeIgniter4,bcit-ci/CodeIgniter4,bcit-ci/CodeIgniter4,kenjis/CodeIgniter4,kenjis/CodeIgniter4,bcit-ci/CodeIgniter4,bcit-ci/CodeIgniter4