core: Add distributed::map_reduce() version which takes a functor
core: Add distributed::map_reduce() version which takes a functor

rentongzhang/scylla,kjniemi/scylla,gwicke/scylla,senseb/scylla,dwdm/scylla,linearregression/seastar,bzero/seastar,sjperkins/seastar,shyamalschandra/seastar,senseb/scylla,ducthangho/imdb,koolhazz/seastar,cloudius-systems/seastar,anzihenry/seastar,leejir/seastar,dreamsxin/seastar,scylladb/scylla-seastar,senseb/scylla,syuu1228/seastar,justintung/scylla,hongliangzhao/seastar,linearregression/scylla,scylladb/scylla,printedheart/seastar,eklitzke/scylla,scylladb/seastar,stamhe/seastar,rluta/scylla,chunshengster/seastar,glommer/scylla,kjniemi/seastar,scylladb/seastar,acbellini/scylla,raphaelsc/scylla,mixja/seastar,kangkot/scylla,bowlofstew/seastar,avikivity/seastar,hongliangzhao/seastar,flashbuckets/seastar,capturePointer/scylla,dwdm/seastar,guiquanz/scylla,justintung/scylla,avikivity/scylla,tempbottle/seastar,scylladb/scylla,syuu1228/seastar,kjniemi/seastar,scylladb/scylla-seastar,avikivity/seastar,wildinto/seastar,stamhe/scylla,jonathanleang/seastar,ducthangho/imdb,aruanruan/scylla,avikivity/seastar,duarten/scylla,justintung/scylla,glommer/scylla,asias/scylla,shaunstanislaus/scylla,wildinto/scylla,scylladb/scylla,xtao/seastar,phonkee/scylla,cloudius-systems/seastar,acbellini/seastar,wildinto/scylla,mixja/seastar,acbellini/seastar,linearregression/scylla,raphaelsc/scylla,tempbottle/scylla,victorbriz/scylla,stamhe/seastar,linearregression/seastar,joerg84/seastar,mixja/seastar,joerg84/seastar,victorbriz/scylla,cloudius-systems/seastar,phonkee/scylla,asias/scylla,stamhe/seastar,jonathanleang/seastar,gwicke/scylla,avikivity/scylla,kjniemi/scylla,rentongzhang/scylla,wildinto/seastar,scylladb/seastar,sjperkins/seastar,guiquanz/scylla,anzihenry/seastar,koolhazz/seastar,kjniemi/scylla,scylladb/scylla-seastar,norcimo5/seastar,rluta/scylla,norcimo5/seastar,dwdm/scylla,stamhe/scylla,linearregression/scylla,dreamsxin/seastar,rentongzhang/scylla,wildinto/scylla,acbellini/scylla,xtao/seastar,leejir/seastar,aruanruan/scylla,chunshengster/seastar,respu/scylla,acbellini/seastar,ducthangho/imdb,dwdm/scylla,aruanruan/scylla,wildinto/seastar,tempbottle/scylla,flashbuckets/seastar,dwdm/seastar,tempbottle/seastar,capturePointer/scylla,stamhe/scylla,koolhazz/seastar,respu/scylla,tempbottle/seastar,shyamalschandra/seastar,printedheart/seastar,dwdm/seastar,bowlofstew/scylla,scylladb/scylla,bzero/seastar,hongliangzhao/seastar,dreamsxin/seastar,gwicke/scylla,bowlofstew/seastar,capturePointer/scylla,syuu1228/seastar,shaunstanislaus/scylla,bowlofstew/scylla,bzero/seastar,leejir/seastar,shyamalschandra/seastar,printedheart/seastar,anzihenry/seastar,glommer/scylla,norcimo5/seastar,bowlofstew/seastar,rluta/scylla,respu/scylla,avikivity/scylla,kangkot/scylla,duarten/scylla,asias/scylla,bowlofstew/scylla,acbellini/scylla,raphaelsc/scylla,eklitzke/scylla,phonkee/scylla,eklitzke/scylla,kangkot/scylla,tempbottle/scylla,linearregression/seastar,xtao/seastar,sjperkins/seastar,guiquanz/scylla,chunshengster/seastar,duarten/scylla,joerg84/seastar,jonathanleang/seastar,shaunstanislaus/scylla,kjniemi/seastar,flashbuckets/seastar,victorbriz/scylla