code: func WithLogContext(ctx context.Context, keyvals ...interface{}) context.Context {
  	logger := ContextLogger(ctx)
  	if logger == nil {
  		return ctx
  	}
  	nl := logger.New(keyvals...)
  	return WithLogger(ctx, nl)
  }
docs: // WithLogContext instantiates a new logger by appending the given key/value pairs to the context
  // logger and setting the resulting logger in the context.