container/stream/attach: use pools.Copy
container/stream/attach: use pools.Copy

The use of pools.Copy avoids io.Copy's internal buffer allocation.
This commit replaces io.Copy with pools.Copy to avoid the allocation of
buffers in io.Copy.

Signed-off-by: Cristian Staretu <78db8d24f2e00709fded2f6f25e9a572f4b7462f@gmail.com>

vdemeester/docker,bonczj/moby-json-file-logger,pradipd/moby,tophj-ibm/docker,tonistiigi/docker,AkihiroSuda/docker,yosifkit/docker,x1022as/docker,laijs/moby,jimjag/docker,pramodhkp/moby,AkihiroSuda/docker,YuPengZTE/docker,flavio/docker,trebonian/docker,gnailuy/docker,ibuildthecloud/docker,amatsus/docker,miminar/docker,rremer/moby,srust/docker,moul/docker,thaJeztah/docker,yongtang/docker,paralin/docker,KarthikNayak/docker,duglin/docker,dccurtis/docker,tmp6154/docker,docker/docker,coolljt0725/docker,ripcurld0/moby,ripcurld0/moby,lixiaobing10051267/docker,laijs/moby,konstruktoid/docker-upstream,scotttlin/docker,SvenDowideit/docker,pramodhkp/moby,mixja/docker,rancher/docker,jimjag/docker,crosbymichael/docker,gnailuy/docker,miminar/docker,JMesser81/docker,rancher/docker,tklauser/docker,mixja/docker,charleszheng44/moby,srust/docker,madhanrm/docker,jvanz/docker,POLJM242/docker,noironetworks/docker,coreos/docker,flavio/docker,dmcgowan/docker,mahak/docker,dsheets/moby,jimjag/docker,crosbymichael/docker,moby/moby,mahak/docker,nawawi/docker,kolyshkin/moby,cyphar/docker,maxamillion/docker,Mokolea/docker,cpuguy83/docker,mikebrow/docker,djs55/docker,danyalKhaliq10p/moby,imkin/moby,moul/docker,pradipd/moby,jwhonce/docker,shhsu/docker,Ramzec/docker,x1022as/docker,mahak/docker,trebonian/docker,estesp/docker,thaJeztah/docker,dims/docker,justincormack/docker,lixiaobing10051267/docker,hqhq/moby,dmcgowan/docker,ndeloof/docker,YuPengZTE/docker,konstruktoid/docker-upstream,jlhawn/docker,paralin/docker,kolyshkin/docker,docker/docker,bearstech/moby,nalind/docker,kojiromike/docker,nawawi/docker,ndeloof/docker,bearstech/moby,yummypeng/docker,liaoqingwei/docker,laijs/moby,KingEmet/docker,Ramzec/docker,jlhawn/docker,allencloud/docker,danyalKhaliq10p/moby,shhsu/docker,bearstech/moby,raja-sami-10p/moby,dperny/docker,whuwxl/docker,fcrisciani/docker,maxamillion/docker,lixiaobing1/docker,moul/docker,pramodhkp/moby,coolljt0725/docker,yongtang/docker,jameszhan/docker,kolyshkin/moby,nawawi/docker,liaoqingwei/docker,ripcurld0/moby,shhsu/docker,charleszheng44/moby,jthelin/docker,charleszheng44/moby,AkihiroSuda/docker,srust/docker,gnailuy/docker,naveed-jamil-tenpearls/moby,KarthikNayak/docker,unclejack/docker,POLJM242/docker,naveed-jamil-tenpearls/moby,shishir-a412ed/docker,mike1729/docker,shishir-a412ed/docker,allencloud/docker,tmp6154/docker,liaoqingwei/docker,ibuildthecloud/docker,rhatdan/docker,danyalKhaliq10p/moby,yummypeng/docker,KingEmet/docker,duglin/docker,hqhq/moby,duglin/docker,thaJeztah/docker,haveatry/docker,maxamillion/docker,noironetworks/docker,jvanz/docker,coreos/docker,whuwxl/docker,jwhonce/docker,PatrickLang/moby,johnstep/moby-moby,konstruktoid/docker-1,mikebrow/docker,raja-sami-10p/moby,Ramzec/docker,kojiromike/docker,jameszhan/docker,kolyshkin/docker,mixja/docker,gnailuy/docker,nalind/docker,jwhonce/docker,kojiromike/docker,djs55/docker,allencloud/docker,cpuguy83/docker,Mokolea/docker,vdemeester/docker,laijs/docker,rremer/moby,cpuguy83/docker,docker/docker,sterchelen/docker,KarthikNayak/docker,ibuildthecloud/docker,AkihiroSuda/docker,fcrisciani/docker,cpuguy83/docker,dperny/docker,ibuildthecloud/docker,tklauser/docker,Ramzec/docker,imkin/moby,JMesser81/docker,JMesser81/docker,shishir-a412ed/docker,resin-io/docker,trebonian/docker,scotttlin/docker,haveatry/docker,fcrisciani/docker,hqhq/moby,scotttlin/docker,bearstech/moby,SvenDowideit/docker,konstruktoid/docker-upstream,PatrickLang/moby,tonistiigi/docker,raja-sami-10p/moby,ibuildthecloud/docker,moul/docker,tonistiigi/docker,crosbymichael/docker,lixiaobing1/docker,kolyshkin/moby,sterchelen/docker,YuPengZTE/docker,PatrickLang/moby,johnstep/moby-moby,coolljt0725/docker,jlhawn/docker,dperny/docker,dsheets/moby,lixiaobing1/docker,yosifkit/docker,tophj-ibm/docker,moby/moby,jimjag/docker,amatsus/docker,paralin/docker,rremer/moby,vdemeester/docker,estesp/docker,trebonian/docker,unclejack/docker,coreos/docker,justincormack/docker,jthelin/docker,jameszhan/docker,moby/moby,bonczj/moby-json-file-logger,tmp6154/docker,tklauser/docker,thaJeztah/docker,dsheets/moby,mahak/docker,bonczj/moby-json-file-logger,madhanrm/docker,mkumatag/docker,konstruktoid/docker-1,SvenDowideit/docker,dims/docker,haveatry/docker,madhanrm/docker,nalind/docker,cyphar/docker,nawawi/docker,sterchelen/docker,dccurtis/docker,dmcgowan/docker,mikebrow/docker,amatsus/docker,tophj-ibm/moby,justincormack/docker,paralin/docker,unclejack/docker,yummypeng/docker,jvanz/docker,KingEmet/docker,yosifkit/docker,noironetworks/docker,mkumatag/docker,flavio/docker,laijs/docker,mike1729/docker,naveed-jamil-tenpearls/moby,dccurtis/docker,moby/moby,lixiaobing10051267/docker,mkumatag/docker,tophj-ibm/moby,flavio/docker,tophj-ibm/docker,konstruktoid/docker-upstream,rhatdan/docker,tophj-ibm/moby,miminar/docker,djs55/docker,resin-io/docker,rhatdan/docker,Mokolea/docker,yongtang/docker,whuwxl/docker,johnstep/moby-moby,Mokolea/docker,mike1729/docker,konstruktoid/docker-1,nalind/docker,dims/docker,pradipd/moby,resin-io/docker,rancher/docker,cyphar/docker,laijs/docker,imkin/moby,estesp/docker,x1022as/docker,ndeloof/docker,yosifkit/docker