Elegant query for Sergii

IEnumerable<Message> messages = await context.Messages
                    .Where(m => m.Recipient_Id == userId || m.Author_Id == userId)
                    .Select(m => new
                    {
                        Partner = m.Recipient_Id == userId ? m.Author_Id : m.Recipient_Id,
                        Message = m
                    })
                    .GroupBy(m => m.Partner)
                    .SelectMany(messageGroup => messageGroup
                        .Where(lastMessage =>
                            lastMessage.Message.Time == messageGroup.Max(m => m.Message.Time))
                        .Take(1))
                    .Select(m => m.Message)
                    .ToListAsync();