def start_time
      @start_time ||= @events.select { |event|
        event.is_a?(RequestWillBeSent)
      }.select { |event|
        event.request['url'] == @url
      }.map { |event|
        event.timestamp
      }.first
    end
def start_time
      @start_time ||= @events.select { |event|
        event.is_a?(RequestWillBeSent)
      }.select { |event|
        event.request['url'] == @url
      }.map { |event|
        event.timestamp
      }.first
    end
The seconds since epoch that the request for this document started