class Faraday::Middleware

def call(env)
  on_request(env) if respond_to?(:on_request)
  app.call(env).on_complete do |environment|
    on_complete(environment) if respond_to?(:on_complete)
  end
rescue StandardError => e
  on_error(e) if respond_to?(:on_error)
  raise
end

def close
  if app.respond_to?(:close)
    app.close
  else
    warn "#{app} does not implement \#close!"
  end
end

def initialize(app = nil, options = {})
  @app = app
  @options = options
end