allow passing in a timers implementation
allow passing in a timers implementation

hustxiaoc/tchannel,chenwenbin928/tchannel,bunnyblue/tchannel,savaki/tchannel,chenwenbin928/tchannel,vanloswang/tchannel,Zirpon/tchannel,benfleis/tchannel,savaki/tchannel,sasa233/tchannel,sasa233/tchannel,hustxiaoc/tchannel,RyanTech/tchannel,RyanTech/tchannel,bunnyblue/tchannel,davewhat/tchannel,sasa233/tchannel,savaki/tchannel,i/tchannel,bunnyblue/tchannel,i/tchannel,hustxiaoc/tchannel,davewhat/tchannel,Zirpon/tchannel,RyanTech/tchannel,vanloswang/tchannel,benfleis/tchannel,benfleis/tchannel,i/tchannel,vanloswang/tchannel,chenwenbin928/tchannel,Zirpon/tchannel