lib/vcr/middleware/rack.rb in vcr-1.9.0 vs lib/vcr/middleware/rack.rb in vcr-1.10.0

@@ -1,12 +1,19 @@
 module VCR
   module Middleware
     class Rack
       include Common
 
+      def initialize(*args)
+        @mutex = Mutex.new
+        super
+      end
+
       def call(env)
-        VCR.use_cassette(*cassette_arguments(env)) do
-          @app.call(env)
+        @mutex.synchronize do
+          VCR.use_cassette(*cassette_arguments(env)) do
+            @app.call(env)
+          end
         end
       end
     end
   end
 end