etcdctl/ctlv3/command/lease_command.go
func leaseKeepAliveCommandFunc(cmd *cobra.Command, args []string) {
	if len(args) != 1 {
		ExitWithError(ExitBadArgs, fmt.Errorf("lease keep-alive command needs lease ID as argument"))
	}

	id := leaseFromArgs(args[0])

	if leaseKeepAliveOnce {
		respc, kerr := mustClientFromCmd(cmd).KeepAliveOnce(context.TODO(), id)
		if kerr != nil {
			ExitWithError(ExitBadConnection, kerr)
		}
		display.KeepAlive(*respc)
		return
	}

	respc, kerr := mustClientFromCmd(cmd).KeepAlive(context.TODO(), id)
	if kerr != nil {
		ExitWithError(ExitBadConnection, kerr)
	}
	for resp := range respc {
		display.KeepAlive(*resp)
	}

	if _, ok := (display).(*simplePrinter); ok {
		fmt.Printf("lease %016x expired or revoked.\n", id)
	}
}
func leaseKeepAliveCommandFunc(cmd *cobra.Command, args []string) {
	if len(args) != 1 {
		ExitWithError(ExitBadArgs, fmt.Errorf("lease keep-alive command needs lease ID as argument"))
	}

	id := leaseFromArgs(args[0])

	if leaseKeepAliveOnce {
		respc, kerr := mustClientFromCmd(cmd).KeepAliveOnce(context.TODO(), id)
		if kerr != nil {
			ExitWithError(ExitBadConnection, kerr)
		}
		display.KeepAlive(*respc)
		return
	}

	respc, kerr := mustClientFromCmd(cmd).KeepAlive(context.TODO(), id)
	if kerr != nil {
		ExitWithError(ExitBadConnection, kerr)
	}
	for resp := range respc {
		display.KeepAlive(*resp)
	}

	if _, ok := (display).(*simplePrinter); ok {
		fmt.Printf("lease %016x expired or revoked.\n", id)
	}
}
// leaseKeepAliveCommandFunc executes the "lease keep-alive" command.