refactor duplication of irate and idelta functions implementations
refactor duplication of irate and idelta functions implementations

SaltedMan/prometheus-annotated,JavierZunzunegui/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,yanghongkjxy/prometheus,ton31337/prometheus,dsymonds/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,Stackdriver/stackdriver-prometheus,Stackdriver/stackdriver-prometheus,Gouthamve/prometheus,JavierZunzunegui/prometheus,tomwilkie/prometheus,dsymonds/prometheus,amorken/prometheus,gottwald/prometheus,slok/prometheus,Conorbro/prometheus,gottwald/prometheus,Colstuwjx/prometheus,Conorbro/prometheus,datajet-io/prometheus,datajet-io/prometheus,AlekSi/prometheus,agaoglu/prometheus,tomwilkie/prometheus,kangwoo/prometheus,msiebuhr/prometheus,agaoglu/prometheus,datajet-io/prometheus,Conorbro/prometheus,adamron1/prometheus,prometheus/prometheus,agaoglu/prometheus,PrFalken/prometheus,amorken/prometheus,dsymonds/prometheus,prometheus/prometheus,Gouthamve/prometheus,Stackdriver/stackdriver-prometheus,dmilstein/prometheus,datajet-io/prometheus,agaoglu/prometheus,ton31337/prometheus,dsymonds/prometheus,prometheus/prometheus,keegancsmith/prometheus,tattsun/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,PrFalken/prometheus,msiebuhr/prometheus,prometheus/prometheus,adamron1/prometheus,SaltedMan/prometheus-annotated,alileza/prometheus,Colstuwjx/prometheus,yanghongkjxy/prometheus,AlekSi/prometheus,gottwald/prometheus,PrFalken/prometheus,AlekSi/prometheus,sudhi-vm/prometheus,tattsun/prometheus,yanghongkjxy/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,tattsun/prometheus,brancz/prometheus,kzittritsch/prometheus,PrFalken/prometheus,gottwald/prometheus,brancz/prometheus,Conorbro/prometheus,Colstuwjx/prometheus,GoogleCloudPlatform/prometheus,sudhi-vm/prometheus,kangwoo/prometheus,tattsun/prometheus,adamron1/prometheus,SaltedMan/prometheus-annotated,adamron1/prometheus,alileza/prometheus,amorken/prometheus,Stackdriver/stackdriver-prometheus,slok/prometheus,alileza/prometheus,msiebuhr/prometheus,tomwilkie/prometheus,amorken/prometheus,ton31337/prometheus,SaltedMan/prometheus-annotated,sudhi-vm/prometheus,AlekSi/prometheus,dmilstein/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,brancz/prometheus,brancz/prometheus,JavierZunzunegui/prometheus,alileza/prometheus,sudhi-vm/prometheus,kangwoo/prometheus,JavierZunzunegui/prometheus,Gouthamve/prometheus,alileza/prometheus,msiebuhr/prometheus,ton31337/prometheus,slok/prometheus,dmilstein/prometheus,GoogleCloudPlatform/prometheus,dmilstein/prometheus,kzittritsch/prometheus,slok/prometheus,Colstuwjx/prometheus,yanghongkjxy/prometheus,tomwilkie/prometheus,kzittritsch/prometheus,kzittritsch/prometheus