Implement Countable interface

[versusbassz]

• https://stackoverflow.com/questions/3721585/using-count-on-a-class-that-implements-iterator-in-php

Seems like impossible, but at least it necessary to provide:

• an example how to count items manually via counter variable
• implement this Output optional debug info after each memory clearing (in CLI SAPI) #9

Notes

• wp_query count only
  • https://wordpress.stackexchange.com/questions/177908/return-only-count-from-a-wp-query-request