Indicate the number of known gaps for NSEC3

[BenBE]

It would be nice if the status line could indicate the number of still open gaps in the zone coverage (their total size is indirectly given by the coverage percentage).

;; mapping tld. 100% [===================================================================================================================================================================] ;;
;; records = 999999; queries =  42; hashes = 1234567890; predicted zone size = 999999; ................................................................... q/s = 0; coverage =  99.999997% ;;

The second line could additionally include some indication like gaps = 5; or similar, to let the user know if n3map is just working on one gap or possibly many small ones.

[anonion0]

Good idea!
This would also be a guaranteed lower bound on the number of remaining records.