pass response parts as a param rather than mutating

lib/capybara/poltergeist/browser.rb

@@ -112,14 +112,11 @@ module Capybara::Poltergeist
     end
 
     def network_traffic
-      response = command 'network_traffic'
-
-      response.values.map do |event|
-        request = NetworkTraffic::Request.new(event['request'])
-        event['responseParts'].each do |response|
-          request.response_parts.push(NetworkTraffic::Response.new(response))
-        end
-        request
+      command('network_traffic').values.map do |event|
+        NetworkTraffic::Request.new(
+          event['request'],
+          event['responseParts'].map { |response| NetworkTraffic::Response.new(response) }
+        )
       end
     end
 

lib/capybara/poltergeist/network_traffic/request.rb

@@ -2,9 +2,9 @@ module Capybara::Poltergeist::NetworkTraffic
   class Request
     attr_reader :response_parts
 
-    def initialize(data)
-      @data = data
-      @response_parts = []
+    def initialize(data, response_parts = [])
+      @data           = data
+      @response_parts = response_parts
     end
 
     def url