[RELEASE] -  publish version:  '1.2.1-rc22'.
[RELEASE] -  publish version:  '1.2.1-rc22'.

wuqiangxjtu/zipkin,rocwzp/zipkin,rocwzp/zipkin,srijs/zipkin,yshaojie/zipkin,lqjack/zipkin,mzagar/zipkin,thelastpickle/zipkin,Yelp/zipkin,betable/zipkin,gneokleo/zipkin,rjbhewei/zipkin,prat0318/zipkin,jfeltesse-mdsol/zipkin,gneokleo/zipkin,lqjack/zipkin,lqjack/zipkin,jstanier/zipkin,rocwzp/zipkin,rjbhewei/zipkin,hydro2k/zipkin,thelastpickle/zipkin,rjbhewei/zipkin,coursera/zipkin,jamescway/zipkin,jfeltesse-mdsol/zipkin,coursera/zipkin,yshaojie/zipkin,mt0803/zipkin,mt0803/zipkin,coursera/zipkin,wuqiangxjtu/zipkin,hydro2k/zipkin,jamescway/zipkin,Yelp/zipkin,jamescway/zipkin,mt0803/zipkin,hydro2k/zipkin,rocwzp/zipkin,mzagar/zipkin,rjbhewei/zipkin,prat0318/zipkin,thelastpickle/zipkin,gneokleo/zipkin,betable/zipkin,srijs/zipkin,Yelp/zipkin,srijs/zipkin,yshaojie/zipkin,yshaojie/zipkin,wuqiangxjtu/zipkin,thelastpickle/zipkin,mzagar/zipkin,mzagar/zipkin,jstanier/zipkin,prat0318/zipkin,hydro2k/zipkin,gneokleo/zipkin,srijs/zipkin,Yelp/zipkin,coursera/zipkin,betable/zipkin,jfeltesse-mdsol/zipkin,prat0318/zipkin,jstanier/zipkin,jstanier/zipkin,mt0803/zipkin,jamescway/zipkin,wuqiangxjtu/zipkin,jfeltesse-mdsol/zipkin,lqjack/zipkin,betable/zipkin