Describe the bug
When the event submission fails because of a network error, Sentry::Transport will log the error and swallow it. The app can't catch the error by itself, besides, Sentry.send_event always return a event object whether the submission is successful or not . When I use Sentry.send_event, I can't tell whether the sumission is failed from errors or returned value. Sidekiq's retry mechanism won't work because there is no error.

Expected behavior
Please raise the error when fail to submit event
Actual behavior
No error is raised when fail to submit event

Environment
Ruby Version: 2.7.2
SDK Version: 4.1.4
Integration Versions (if any):
Rails 6.0.3.4, Sidekiq 6.1.2

Raven Config

This is not necessary but could be helpful.

    Sentry.init do |config|
      config.breadcrumbs_logger = [:active_support_logger]
      config.async = lambda { |event, hint| SentryWorker.perform_async(event, hint) }
      config.enabled_environments = %w(production)
      config.send_modules = false
      config.context_lines = 1
      config.transport.open_timeout = 2
    end