When the callback queue is the main queue, don't wrap in another serial queue. (#245)
When the callback queue is the main queue, don't wrap in another serial queue. (#245)


google/gtm-session-fetcher,thomasvl/gtm-session-fetcher,google/gtm-session-fetcher,thomasvl/gtm-session-fetcher,google/gtm-session-fetcher,thomasvl/gtm-session-fetcher