* Fix a bug where TLS would become None
The bug is invoked as follows:
- Runner 1 is created and stores the current version of the TLS
LOCAL_QUEUE variable, which is None.
- Runner 2 is also created. It stores the current version of the TLS
variable as well, which is Runner 1's queue.
- Runner 1 is dropped. It stores None into the LOCAL_QUEUE variable.
- Runner 2 tries to run. It reads from the LOCAL_QUEUE variable, sees
that it is None, and panics.
This could be solved by just not using the local queue if the variable
is None. However, we can do one better; if the slot is open, we can
optimize the runner by replacing it with our own queue. This should
allow for the local queue to be used more often.
Closes#54
Signed-off-by: John Nunley <dev@notgull.net>
John Nunley
Taiki Endo
Stjepan Glavina