handler: downgrade missing headers to warnings
handler: downgrade missing headers to warnings

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