old nginx workers cannot shut down properly when nginx reload because timers won't exit

[neoyk]

lua-resty-rocketmq/lib/resty/rocketmq/consumer.lua

Line 556 in dff8f2a

ngx_timer_at(0, function()

none of the timers in this repo has a parameter named premature without it timers cannot get notified when nginx reload thus won't exit during reload
nginx worker cannot shutdown properly when timers won't stop

it's advisable to add premature parameter in timer functions to get notified when nginx reload and exit timers ASAP