func (s *LoggerServer) FollowLog(_ *FollowLogRequest, stream LoggerService_FollowLogServer) error {
	logger := s.V.GetFeature((*log.Instance)(nil))
	if logger == nil {
		return newError("unable to get logger instance")
	}
	follower, ok := logger.(cmlog.Follower)
	if !ok {
		return newError("logger not support following")
	}
	var err error
	f := func(msg cmlog.Message) {
		err = stream.Send(&FollowLogResponse{
			Message: msg.String(),
		})
	}
	follower.AddFollower(f)
	defer follower.RemoveFollower(f)
	ticker := time.NewTicker(time.Second)
	for {
		<-ticker.C
		if err != nil {
			ticker.Stop()
			return nil
		}
	}
}
FollowLog implements LoggerService.
package command
import (
	"context"
	"time"
	grpc "google.golang.org/grpc"
	core "github.com/v2fly/v2ray-core/v4"
	"github.com/v2fly/v2ray-core/v4/app/log"
	"github.com/v2fly/v2ray-core/v4/common"
	cmlog "github.com/v2fly/v2ray-core/v4/common/log"
)
type LoggerServer struct {
	V *core.Instance
}
func (s *LoggerServer) RestartLogger(ctx context.Context, request *RestartLoggerRequest) (*RestartLoggerResponse, error) {
	logger := s.V.GetFeature((*log.Instance)(nil))
	if logger == nil {
		return nil, newError("unable to get logger instance")
	}
	if err := logger.Close(); err != nil {
		return nil, newError("failed to close logger").Base(err)
	}
	if err := logger.Start(); err != nil {
		return nil, newError("failed to start logger").Base(err)
	}
	return &RestartLoggerResponse{}, nil
}