Fix buffer_test failure caused by uint32 vs uint64 comparison
Fix buffer_test failure caused by uint32 vs uint64 comparison

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