server: avoid an unnecessary allocation per-RPC for OK status (#2920)
server: avoid an unnecessary allocation per-RPC for OK status (#2920)


menghanl/grpc-go,dfawley/grpc-go,menghanl/grpc-go,stanley-cheung/grpc-go,grpc/grpc-go,stanley-cheung/grpc-go,grpc/grpc-go,dfawley/grpc-go