Major - P3 estimated_document_count prohibits find conditions:
irb(main):008:0> a['foo'].find(a:1).estimated_document_count
Traceback (most recent call last):
5: from /home/w/.rbenv/versions/2.7/bin/irb:23:in `<main>'
4: from /home/w/.rbenv/versions/2.7/bin/irb:23:in `load'
3: from /home/w/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/irb-1.2.6/exe/irb:11:in `<top (required)>'
2: from (irb):8
1: from /home/w/apps/ruby-driver/lib/mongo/collection/view/readable.rb:230:in `estimated_document_count'
ArgumentError (Cannot call estimated_document_count when querying with a filter)
However it does not prohibit skip and limit constraints:
irb(main):009:0> a['foo'].find.skip(4).estimated_document_count => 10 irb(main):010:0> a['foo'].find.limit(4).estimated_document_count => 10