Undefined method 'close' when config.backlog set to false

[williantenfen]

• Airbrake version: airbrake (13.0.4) - airbrake-ruby (6.2.2)
• Ruby version: 3.1.6
• Framework name & version: Rails 7.0.8.6

#### Airbrake config

   Airbrake.configure do |c|
  # You must set both project_id & project_key. To find your project_id and
  # project_key navigate to your project's General Settings and copy the values
  # from the right sidebar.
  # https://github.com/airbrake/airbrake-ruby#project_id--project_key
  c.project_id = ENV.fetch("AIRBRAKE_APP_ID", nil)
  c.project_key = ENV.fetch("AIRBRAKE_KEY", nil)

  # Configures the root directory of your project. Expects a String or a
  # Pathname, which represents the path to your project. Providing this option
  # helps us to filter out repetitive data from backtrace frames and link to
  # GitHub files from our dashboard.
  # https://github.com/airbrake/airbrake-ruby#root_directory
  c.root_directory = Rails.root

  # By default, Airbrake Ruby outputs to STDOUT. In Rails apps it makes sense to
  # use the Rails' logger.
  # https://github.com/airbrake/airbrake-ruby#logger
  c.logger = Airbrake::Rails.logger

  # Configures the environment the application is running in. Helps the Airbrake
  # dashboard to distinguish between exceptions occurring in different
  # environments.
  # NOTE: This option must be set in order to make the 'ignore_environments'
  # option work.
  # https://github.com/airbrake/airbrake-ruby#environment
  c.environment = Rails.env

  # Setting this option allows Airbrake to filter exceptions occurring in
  # unwanted environments such as :test.
  # NOTE: This option *does not* work if you don't set the 'environment' option.
  # https://github.com/airbrake/airbrake-ruby#ignore_environments
  c.ignore_environments = %w(test development)

  # A list of parameters that should be filtered out of what is sent to
  # Airbrake. By default, all "password" attributes will have their contents
  # replaced.
  # https://github.com/airbrake/airbrake-ruby#blocklist_keys
  c.blocklist_keys = [/password/i, /authorization/i]

  # Alternatively, you can integrate with Rails' filter_parameters.
  # Read more: https://goo.gl/gqQ1xS
  # c.blocklist_keys = Rails.application.config.filter_parameters

  c.performance_stats = !Rails.env.test?

  c.remote_config = !Rails.env.test?
  c.backlog = false
end

Description

When using config.backlog = false , performance_notifier tries to call .close from empty @backlog instance:

airbrake-ruby-6.2.2/lib/airbrake-ruby/sync_sender.rb:69:in `close': undefined method `close' for nil:NilClass (NoMethodError)
      @backlog.close
              ^^^^^^
  from /Users/.../.asdf/installs/ruby/3.1.6/lib/ruby/gems/3.1.0/gems/airbrake-ruby-6.2.2/lib/airbrake-ruby/performance_notifier.rb:53:in `block in close'
...

PR with suggested fix: airbrake/airbrake-ruby#731

[williantenfen]

@thompiler @mmcdaris