code: func flagTimeout(fs *flag.FlagSet, addr *time.Duration, def string) {
  	t, _ := time.ParseDuration(def)
  	fs.DurationVarP(
  		addr,
  		"timeout",
  		"t",
  		t,
  		`A duration string that specifies the timeout used for gRPC operations.
          Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", and
          "h"`)
  }
docs: // flagTimeout adds the -t,--timeout flag to the specified flagset.