How to get accurate SimpleCov coverage with Spring in a Rails application

environment.rb

# Load the Rails application.
require_relative 'application'

# Initialize the Rails application.
Rails.application.initialize!

if defined?(Spring) && defined?(SimpleCov) && Coverage.running?
  SimpleCov.spring_preload_result = Coverage.peek_result
end

Gemfile

group :development, :test do
  gem 'spring-commands-rspec', require: false
  gem 'spring-watcher-listen', require: false
  gem 'spring', require: false
  # ...
end

rails_helper.rb

require 'spec_helper'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../config/environment', __dir__)

# Eager load all files so that SimpleCov reports accurate coverage.
Rails.application.eager_load!

spec_helper.rb

# If we are using Spring, then SimpleCov is started in config/spring.rb
unless defined?(Spring)
  require 'simplecov'
  SimpleCov.command_name 'RSpec'
  SimpleCov.start 'rails'
end

spring.rb

if ENV['RAILS_ENV'] == 'test'
  require 'simplecov'

  SimpleCov.class_eval do
    class << self
      attr_accessor :spring_preload_result

      # Returns the result for the current coverage run, merging it across test suites
      # from cache using SimpleCov::ResultMerger if use_merging is activated (default).
      # If Spring is used, we merge in coverage from the preloaded Rails app.
      def result
        return @result if result?

        # Collect our coverage result
        if running
          raw_result = add_not_loaded_files(Coverage.result)
          if SimpleCov.spring_preload_result
            raw_result = SimpleCov::RawCoverage.merge_results(
              SimpleCov.spring_preload_result,
              raw_result
            )
          end
          @result = SimpleCov::Result.new(raw_result)
        end

        # If we're using merging of results, store the current result
        # first (if there is one), then merge the results and return those
        if use_merging
          SimpleCov::ResultMerger.store_result(@result) if result?
          @result = SimpleCov::ResultMerger.merged_result
        end

        @result
      ensure
        self.running = false
      end
    end
  end

  SimpleCov.command_name 'RSpec'
  SimpleCov.start 'rails'

  # Prevent SimpleCov from writing test coverage after the Spring process exits
  SimpleCov.pid = nil
end

Spring.after_fork do
  next unless Rails.env.test?

  # Ensure that SimpleCov writes test coverage for this process
  SimpleCov.pid = Process.pid
end

How to make this work with Simplecov >= 0.18.0 ? It seems that they removed SimpleCov::RawCoverage