add Function2 interface.
add Function2 interface.

twitter/util,LitmusHealth/twitter-utils,RUNDSP/util,luciferous/util,nkhuyu/util,travisbrown/util,slackhappy/util,Jiri-Kremser/util,cogitate/twitter-util-uuid,edombowsky/util,nkhuyu/util,BuoyantIO/twitter-util,tdyas/util,LitmusHealth/twitter-utils,slackhappy/util,BuoyantIO/twitter-util,luciferous/util,Jiri-Kremser/util,stremlenye/util,Jiri-Kremser/util,BuoyantIO/twitter-util,nkhuyu/util,BuoyantIO/twitter-util,mosesn/util,folone/util,slackhappy/util,folone/util,tdyas/util,wuqiangxjtu/util,edombowsky/util,Jiri-Kremser/util,stremlenye/util,folone/util,RUNDSP/util,travisbrown/util,tenghuihua/util,folone/util,twitter/util,slackhappy/util,cogitate/twitter-util-uuid,edombowsky/util,tenghuihua/util,hydro2k/util,cogitate/twitter-util-uuid,mosesn/util,wuqiangxjtu/util,mosesn/util,twitter/util,tdyas/util,nkhuyu/util,stremlenye/util,hydro2k/util,travisbrown/util,travisbrown/util,luciferous/util,tdyas/util,wuqiangxjtu/util,tenghuihua/util,RUNDSP/util,LitmusHealth/twitter-utils,edombowsky/util,luciferous/util,hydro2k/util,LitmusHealth/twitter-utils,hydro2k/util,tenghuihua/util,wuqiangxjtu/util,cogitate/twitter-util-uuid,RUNDSP/util,stremlenye/util