breakpad/crashpad signal handler doesn't work in WIOService threads
We encountered this issue when using Sentry: https://github.com/getsentry/sentry-native/issues/432
WIOService's worker threads block all signals. As far as I understand this is to make sure that signals are handled in the main thread, since we can't be sure which thread will handle the signal. There are some exceptional signals that are always sent to a specific thread though (called thread-directed signals) (see https://stackoverflow.com/a/6533431):
I think the solution to make crashpad/breakpad and thus Sentry work properly is to unblock those four signals.