Use a sync.pool for the staging buffer in codec.go.
Use a sync.pool for the staging buffer in codec.go.

Change-Id: I1aae6847f77b5a7c75582b07c199b1943cf90552

JavierZunzunegui/prometheus,Conorbro/prometheus,iksaif/prometheus,gcnonato/prometheus,brancz/prometheus,nicr9/prometheus,abhishekamralkar/prometheus,PrFalken/prometheus,justintung/prometheus,cit-lab/prometheus,tomwilkie/prometheus,kangwoo/prometheus,gottwald/prometheus,msiebuhr/prometheus,JavierZunzunegui/prometheus,q3k/prometheus,prometheus/prometheus,prasincs/prometheus,ton31337/prometheus,jimmidyson/prometheus,kzittritsch/prometheus,mrwacky42/prometheus,adamron1/prometheus,fabxc/prometheus,rajthilakmca/prometheus,thachmai/prometheus,nicr9/prometheus,trigrass2/prometheus,jmcfarlane/prometheus,robbiet480/prometheus,keegancsmith/prometheus,gcnonato/prometheus,RobertKielty/prometheus,cit-lab/prometheus,yanghongkjxy/prometheus,Colstuwjx/prometheus,dsymonds/prometheus,GoogleCloudPlatform/prometheus,eliothedeman/prometheus,jbdalido/prometheus,dln/prometheus,GoogleCloudPlatform/prometheus,dalanlan/prometheus,keegancsmith/prometheus,kzittritsch/prometheus,prometheus/prometheus,nicr9/prometheus,sudhi-vm/prometheus,agaoglu/prometheus,kangwoo/prometheus,amorken/prometheus,wrouesnel/prometheus,abhishekamralkar/prometheus,msiebuhr/prometheus,q3k/prometheus,Stackdriver/stackdriver-prometheus,gcnonato/prometheus,jmcfarlane/prometheus,JavierZunzunegui/prometheus,robbiet480/prometheus,flier/prometheus,justintung/prometheus,tomwilkie/prometheus,wxdublin/prometheus,brancz/prometheus,sudhi-vm/prometheus,gcnonato/prometheus,fabric8io/prometheus,tattsun/prometheus,mtanda/prometheus,prasincs/prometheus,yanghongkjxy/prometheus,tattsun/prometheus,mtanda/prometheus,fabric8io/prometheus,jbdalido/prometheus,amorken/prometheus,bluecmd/prometheus,smyrman/prometheus,slok/prometheus,Conorbro/prometheus,datajet-io/prometheus,smyrman/prometheus,AlekSi/prometheus,AlekSi/prometheus,laushinka/prometheus,Dieterbe/prometheus,abhishekamralkar/prometheus,SaltedMan/prometheus-annotated,slok/prometheus,wrouesnel/prometheus,Gouthamve/prometheus,adamron1/prometheus,tomwilkie/prometheus,prometheus/prometheus,PrFalken/prometheus,wndhydrnt/prometheus,SaltedMan/prometheus-annotated,keegancsmith/prometheus,keegancsmith/prometheus,dln/prometheus,iksaif/prometheus,rajthilakmca/prometheus,fabric8io/prometheus,dln/prometheus,kangwoo/prometheus,smyrman/prometheus,rajthilakmca/prometheus,laushinka/prometheus,hustbill/prometheus,adamron1/prometheus,q3k/prometheus,gottwald/prometheus,brancz/prometheus,PrFalken/prometheus,flier/prometheus,keegancsmith/prometheus,mrwacky42/prometheus,slok/prometheus,sudhi-vm/prometheus,laushinka/prometheus,alileza/prometheus,gesellix/prometheus,tomwilkie/prometheus,jmcfarlane/prometheus,wxdublin/prometheus,Stackdriver/stackdriver-prometheus,alileza/prometheus,AlekSi/prometheus,jbdalido/prometheus,gesellix/prometheus,prasincs/prometheus,Conorbro/prometheus,dsymonds/prometheus,eliothedeman/prometheus,hustbill/prometheus,prometheus/prometheus,thachmai/prometheus,abhishekamralkar/prometheus,gesellix/prometheus,JavierZunzunegui/prometheus,kzittritsch/prometheus,wrouesnel/prometheus,fabxc/prometheus,wndhydrnt/prometheus,Stackdriver/stackdriver-prometheus,kzittritsch/prometheus,agaoglu/prometheus,amorken/prometheus,Dieterbe/prometheus,GoogleCloudPlatform/prometheus,eliothedeman/prometheus,GoogleCloudPlatform/prometheus,RobertKielty/prometheus,dmilstein/prometheus,PrFalken/prometheus,bluecmd/prometheus,Colstuwjx/prometheus,trigrass2/prometheus,justintung/prometheus,SaltedMan/prometheus-annotated,gottwald/prometheus,yanghongkjxy/prometheus,mrwacky42/prometheus,thachmai/prometheus,ton31337/prometheus,ton31337/prometheus,q3k/prometheus,msiebuhr/prometheus,jimmidyson/prometheus,dpatel06/prometheus,dpatel06/prometheus,wrouesnel/prometheus,tattsun/prometheus,ton31337/prometheus,gottwald/prometheus,dsymonds/prometheus,jmcfarlane/prometheus,Dieterbe/prometheus,Conorbro/prometheus,Gouthamve/prometheus,dmilstein/prometheus,mtanda/prometheus,dln/prometheus,alileza/prometheus,dmilstein/prometheus,sudhi-vm/prometheus,Gouthamve/prometheus,laushinka/prometheus,flier/prometheus,dmilstein/prometheus,cit-lab/prometheus,mtanda/prometheus,thachmai/prometheus,fabric8io/prometheus,alileza/prometheus,robbiet480/prometheus,bluecmd/prometheus,adamron1/prometheus,bluecmd/prometheus,datajet-io/prometheus,dpatel06/prometheus,RobertKielty/prometheus,rajthilakmca/prometheus,prasincs/prometheus,tattsun/prometheus,Gouthamve/prometheus,GoogleCloudPlatform/prometheus,cit-lab/prometheus,dalanlan/prometheus,datajet-io/prometheus,eliothedeman/prometheus,Colstuwjx/prometheus,alileza/prometheus,agaoglu/prometheus,kangwoo/prometheus,jimmidyson/prometheus,smyrman/prometheus,jbdalido/prometheus,gesellix/prometheus,brancz/prometheus,hustbill/prometheus,wxdublin/prometheus,robbiet480/prometheus,slok/prometheus,dsymonds/prometheus,hustbill/prometheus,fabxc/prometheus,RobertKielty/prometheus,trigrass2/prometheus,SaltedMan/prometheus-annotated,Colstuwjx/prometheus,AlekSi/prometheus,iksaif/prometheus,justintung/prometheus,msiebuhr/prometheus,dalanlan/prometheus,datajet-io/prometheus,iksaif/prometheus,amorken/prometheus,yanghongkjxy/prometheus,fabxc/prometheus,trigrass2/prometheus,prometheus/prometheus,agaoglu/prometheus,Stackdriver/stackdriver-prometheus,wndhydrnt/prometheus