Sigma filters

[myoung34]

Any plans to implement sigma filters ?

[bradleyjkemp]

Interesting, I missed the announcement of these.

My initial thoughts are this:

1. We add support for parsing these into the sigma.Rule struct (add a new filter field)
2. Add a WithFilters option to the evaluator which takes a filter/filters. Then when calling Matches() on the evaluator, this filter will automatically be run before the rule

I don't have any immediate need for these, so don't have any plans to implement them in the short-term, but I think this library should support them in future. Definitely open to PRs (though some more design/exploration would be a good first step)