domain -> rules index for AdblockRules
domain -> rules index for AdblockRules

When domain is the only supported option and re2 is used
this can result in 100x+ speedup for default EasyList filter; if
there are other options speedup is smaller, but still big
(e.g. 20x if supported options are 'domain' and 'script').

scrapinghub/adblockparser