Document stats produced by Scrapy

[mohmad-null]

Documentation bug

Scrapy exposes stats through the crawler.stats, however the stats themselves are not documented.

I have these values:

'log_count/DEBUG' = {int} 983
'log_count/INFO' = {int} 201
'start_time' = {datetime} 2024-05-09 14:51:37.927572+00:00
'scheduler/enqueued/memory' = {int} 1238
'scheduler/enqueued' = {int} 1238
'scheduler/dequeued/memory' = {int} 793
'scheduler/dequeued' = {int} 793
'downloader/request_count' = {int} 183
'downloader/request_method_count/GET' = {int} 183
'downloader/request_bytes' = {int} 61189
'downloader/response_count' = {int} 182
'downloader/response_status_count/200' = {int} 163
'downloader/response_bytes' = {int} 814553
'response_received_count' = {int} 182
'downloader/response_status_count/410' = {int} 19
'request_depth_max' = {int} 3
'log_count/WARNING' = {int} 19

Some of them are fairly self evident (i.e. log counts), but there's nothing anywhere in the docs for the scheduler related ones: dequeued, or enqueued, or the memory subsets.
https://docs.scrapy.org/en/latest/search.html?q=dequeued&check_keywords=yes&area=default
https://docs.scrapy.org/en/latest/search.html?q=enqueued&check_keywords=yes&area=default