gistfile1.rb

#prone to cursor timeouts:
def old
  thing.find(query, options).each do |item|
    Enumerator.new do |y|
      y << do_formatting_and_stuff(item)
    end
  end
end

#immune to cursor timeouts?  the block form of find can be run with an infinite timeout cursor.
def new
  Enumerator.new do |y|
    thing.find(query, options.merge({timeout: false})).each do |cursor|
      cursor.each do |item|
          y << do_formatting_and_stuff(item)
      end
    end
  end
end