Be more explicit about the contract for free_fn in the gpr_allocation_functions doc.
Be more explicit about the contract for free_fn in the gpr_allocation_functions doc.

chrisdunelm/grpc,PeterFaiman/ruby-grpc-minimal,thinkerou/grpc,matt-kwong/grpc,PeterFaiman/ruby-grpc-minimal,philcleveland/grpc,matt-kwong/grpc,hstefan/grpc,kpayson64/grpc,MakMukhi/grpc,dgquintas/grpc,Crevil/grpc,jtattermusch/grpc,fuchsia-mirror/third_party-grpc,vjpai/grpc,sreecha/grpc,adelez/grpc,mehrdada/grpc,kpayson64/grpc,matt-kwong/grpc,sreecha/grpc,carl-mastrangelo/grpc,kumaralokgithub/grpc,MakMukhi/grpc,quizlet/grpc,ncteisen/grpc,nicolasnoble/grpc,firebase/grpc,geffzhang/grpc,7anner/grpc,ncteisen/grpc,jboeuf/grpc,pszemus/grpc,ejona86/grpc,makdharma/grpc,kriswuollett/grpc,sreecha/grpc,mehrdada/grpc,dgquintas/grpc,hstefan/grpc,baylabs/grpc,dgquintas/grpc,vjpai/grpc,makdharma/grpc,philcleveland/grpc,daniel-j-born/grpc,kskalski/grpc,matt-kwong/grpc,carl-mastrangelo/grpc,deepaklukose/grpc,chrisdunelm/grpc,ipylypiv/grpc,adelez/grpc,yongni/grpc,thinkerou/grpc,donnadionne/grpc,geffzhang/grpc,ctiller/grpc,deepaklukose/grpc,kumaralokgithub/grpc,quizlet/grpc,firebase/grpc,muxi/grpc,quizlet/grpc,yang-g/grpc,sreecha/grpc,makdharma/grpc,daniel-j-born/grpc,philcleveland/grpc,Crevil/grpc,jtattermusch/grpc,Crevil/grpc,vsco/grpc,pszemus/grpc,vjpai/grpc,MakMukhi/grpc,dgquintas/grpc,msmania/grpc,carl-mastrangelo/grpc,nicolasnoble/grpc,vsco/grpc,pszemus/grpc,stanley-cheung/grpc,MakMukhi/grpc,muxi/grpc,dgquintas/grpc,thinkerou/grpc,grpc/grpc,quizlet/grpc,PeterFaiman/ruby-grpc-minimal,jboeuf/grpc,thinkerou/grpc,carl-mastrangelo/grpc,yang-g/grpc,kriswuollett/grpc,nicolasnoble/grpc,ejona86/grpc,kriswuollett/grpc,donnadionne/grpc,sreecha/grpc,Crevil/grpc,dgquintas/grpc,ipylypiv/grpc,kriswuollett/grpc,daniel-j-born/grpc,matt-kwong/grpc,vsco/grpc,donnadionne/grpc,donnadionne/grpc,nicolasnoble/grpc,muxi/grpc,mehrdada/grpc,yang-g/grpc,adelez/grpc,geffzhang/grpc,7anner/grpc,baylabs/grpc,donnadionne/grpc,jtattermusch/grpc,vsco/grpc,donnadionne/grpc,fuchsia-mirror/third_party-grpc,grpc/grpc,ncteisen/grpc,ipylypiv/grpc,yang-g/grpc,simonkuang/grpc,ipylypiv/grpc,Vizerai/grpc,ctiller/grpc,zhimingxie/grpc,jtattermusch/grpc,yongni/grpc,vsco/grpc,makdharma/grpc,stanley-cheung/grpc,Crevil/grpc,ejona86/grpc,ncteisen/grpc,simonkuang/grpc,thinkerou/grpc,grpc/grpc,thinkerou/grpc,fuchsia-mirror/third_party-grpc,baylabs/grpc,quizlet/grpc,ctiller/grpc,baylabs/grpc,grpc/grpc,firebase/grpc,vjpai/grpc,Vizerai/grpc,adelez/grpc,ejona86/grpc,geffzhang/grpc,Crevil/grpc,Vizerai/grpc,murgatroid99/grpc,kpayson64/grpc,mehrdada/grpc,thinkerou/grpc,Vizerai/grpc,quizlet/grpc,vsco/grpc,ctiller/grpc,PeterFaiman/ruby-grpc-minimal,MakMukhi/grpc,philcleveland/grpc,murgatroid99/grpc,msmania/grpc,geffzhang/grpc,fuchsia-mirror/third_party-grpc,carl-mastrangelo/grpc,Vizerai/grpc,ipylypiv/grpc,grpc/grpc,7anner/grpc,yang-g/grpc,ejona86/grpc,matt-kwong/grpc,carl-mastrangelo/grpc,carl-mastrangelo/grpc,philcleveland/grpc,dgquintas/grpc,makdharma/grpc,ejona86/grpc,stanley-cheung/grpc,jboeuf/grpc,Vizerai/grpc,fuchsia-mirror/third_party-grpc,pszemus/grpc,msmania/grpc,jtattermusch/grpc,jboeuf/grpc,murgatroid99/grpc,muxi/grpc,firebase/grpc,kpayson64/grpc,simonkuang/grpc,vjpai/grpc,mehrdada/grpc,donnadionne/grpc,donnadionne/grpc,vjpai/grpc,dgquintas/grpc,firebase/grpc,kskalski/grpc,thinkerou/grpc,Crevil/grpc,murgatroid99/grpc,geffzhang/grpc,hstefan/grpc,fuchsia-mirror/third_party-grpc,stanley-cheung/grpc,hstefan/grpc,kumaralokgithub/grpc,pszemus/grpc,deepaklukose/grpc,kriswuollett/grpc,hstefan/grpc,stanley-cheung/grpc,sreecha/grpc,nicolasnoble/grpc,pszemus/grpc,Vizerai/grpc,7anner/grpc,carl-mastrangelo/grpc,jtattermusch/grpc,vjpai/grpc,mehrdada/grpc,muxi/grpc,yang-g/grpc,nicolasnoble/grpc,vjpai/grpc,mehrdada/grpc,stanley-cheung/grpc,jtattermusch/grpc,thinkerou/grpc,stanley-cheung/grpc,thinkerou/grpc,ipylypiv/grpc,yang-g/grpc,muxi/grpc,PeterFaiman/ruby-grpc-minimal,kpayson64/grpc,yang-g/grpc,yongni/grpc,deepaklukose/grpc,ncteisen/grpc,7anner/grpc,carl-mastrangelo/grpc,vsco/grpc,murgatroid99/grpc,PeterFaiman/ruby-grpc-minimal,jboeuf/grpc,firebase/grpc,grpc/grpc,murgatroid99/grpc,yang-g/grpc,philcleveland/grpc,ncteisen/grpc,geffzhang/grpc,ncteisen/grpc,kriswuollett/grpc,firebase/grpc,kriswuollett/grpc,7anner/grpc,firebase/grpc,kumaralokgithub/grpc,jboeuf/grpc,sreecha/grpc,hstefan/grpc,hstefan/grpc,ipylypiv/grpc,hstefan/grpc,nicolasnoble/grpc,geffzhang/grpc,adelez/grpc,quizlet/grpc,kriswuollett/grpc,daniel-j-born/grpc,jtattermusch/grpc,zhimingxie/grpc,firebase/grpc,stanley-cheung/grpc,matt-kwong/grpc,vjpai/grpc,kumaralokgithub/grpc,vjpai/grpc,daniel-j-born/grpc,zhimingxie/grpc,stanley-cheung/grpc,matt-kwong/grpc,deepaklukose/grpc,sreecha/grpc,grpc/grpc,ejona86/grpc,zhimingxie/grpc,mehrdada/grpc,adelez/grpc,fuchsia-mirror/third_party-grpc,MakMukhi/grpc,chrisdunelm/grpc,murgatroid99/grpc,ctiller/grpc,quizlet/grpc,ctiller/grpc,msmania/grpc,pszemus/grpc,kpayson64/grpc,kskalski/grpc,MakMukhi/grpc,baylabs/grpc,adelez/grpc,kskalski/grpc,pszemus/grpc,daniel-j-born/grpc,geffzhang/grpc,7anner/grpc,jtattermusch/grpc,carl-mastrangelo/grpc,kpayson64/grpc,thinkerou/grpc,ejona86/grpc,murgatroid99/grp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