You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: collector.rb
    path of file: ./repos/client_ruby/lib/prometheus/middleware
    
    the code of the file until where you have to start completion: # encoding: UTF-8

require 'benchmark'
require 'prometheus/client'

module Prometheus
  module Middlewa
    
      def trace(env)
        response = nil
        duration = Benchmark.realtime { response = yield }
        record(env, response.first.to_s, duration)
        return response
      rescue => exception
        @exceptions.increment(labels: { exception: exception.class.name })
        raise
      end