Methods
This are the methods we recognize:
init
init the queue (currently noop)
add append argument to the queue
clear
Clear the queue
find_by_pid
Find the index of helper with specified pid
find_by_wheelid
Find the index of helper with specified wheel id
remove_by_pid
Remove helper with specified pid
remove_by_wheelid
Remove helper with specified wheel id
next
Get next helper off the head of the queue (and put it back on the end (round robin))
make_next
Force the helper with the specified wheel id to the head of the queue.
exit_all
Tell all our helpers to exit gracefully.
kill_all
Send the specified signal (default SIGTERM) to all helper processes