def each
      @sources.each_with_index do |source, index|
        include_header =
          case @header_frequency
          when :start
            index == 0
          when Integer
            index % @header_frequency == 0
          else
            @header_frequency
          end
        yield body_row(source, with_header: include_header)
      end
    end
def each
      @sources.each_with_index do |source, index|
        include_header =
          case @header_frequency
          when :start
            index == 0
          when Integer
            index % @header_frequency == 0
          else
            @header_frequency
          end
        yield body_row(source, with_header: include_header)
      end
    end
Calls the given block once for each {Row} in the Table, passing that {Row} as parameter.

 @example
   table.each do |row|
     puts row
   end

 Note that when printed, the first row will visually include the headers (assuming these
 were not disabled when the Table was initialized).