matomo-sdk-ios: Crash with 4.3.0 version

Hi guys,

I upgrade piwik-sdk-ios to 4.3.0 in our new version and public to external beta testing. But I got two new kinds of crash reports from beta users. Here is the crash 1 and crash 2 Looks like it occurred when the SDK dispatch to send request.

Any idea?

BTW, I will upgrade sdk to 4.4.0 in the new beta build.