# File lib/mongo/cursor.rb, line 245
    def batch_size(size=nil)
      return @batch_size unless size
      check_modifiable
      if size < 0 || size == 1
        raise ArgumentError, "Invalid value for batch_size #{size}; must be 0 or > 1."
      else
        @batch_size = @limit != 0 && size > @limit ? @limit : size
      end

      self
    end