PHP 7.4 Warning: count(): Parameter must be an array or an object

hi,
I’m trying your plugin, features useful and successful.
but there are some bugs in the plugin. for example here:

page : ..plugins/fulltext-search/includes/wpfts_index.php
function : public function indexWordData($wid)
this row : $this->logtime(‘set ‘.count($row3).’ doc ids (‘.$pk_size.’,’.strlen($pk).’)’);
and : $this->logtime(‘set remaining ‘.count($row3).’ doc ids (‘.$pk_size.’,’.strlen($pk).’)’);

error : PHP Warning: count($row3): Parameter must be an array or an object that implements Countable,

Is it possible to check it and fix it?

info wpfts_v1.38.106 wp_v5.5.3 php_v7.4.9-x64