ROS 2 context shutdown doesn't play nice with email context shutdown #247
Description
- The polling manager thread isn't properly shut down and joined.
- There seems to be an error in the shut down order/context-related objects lifetime that produces a segfault.
- There's sometimes segfault on shutdown inside
email::EmailReceiver::execute/email::CurlContext::execute/curl_easy_perform. It might be still trying to execute a request when we're trying to shut down.