RegisterShutdown to register a callback to occur when a process exits fatally.

EnvDebug is the environment variable that's tested to see if debugging should be turned on.

EnvDebugDieFast if set to true, die immediately for testing.

EnvSentryUrl to use for logging application logs and errors.

EnvSilentMode to enable when no logging should happen (including Fatal).

LoggingServerContext is the context that we use in the error messages to identify logging related errors.

sentryExitTime to take when exiting while logging.