def request_count_by_resource(resource_type)
      @events.select {|n|
        n.is_a?(ResponseReceived) && n.resource_type == resource_type
      }.size
    end
def request_count_by_resource(resource_type)
      @events.select {|n|
        n.is_a?(ResponseReceived) && n.resource_type == resource_type
      }.size
    end
the number of network requests of a particular resource
 type that were required to load this document

 Possible resource types: 'Document', 'Script', 'Image', 'Stylesheet',
 'Other'.