Message Service

public MessageService( IDbContextFactory<NumaContext> dbContextFactory )
{
    _dbContextFactory = dbContextFactory ?? throw new ArgumentNullException( nameof( dbContextFactory ) );
}

using Numa.Models;

namespace Numa.Interfaces
{
    public interface IMessageService
    {
        Task<List<Message>> GetMessagesByConversationIdAsync( string conversationId );
        Task AddMessageAsync(Message newMessage);
    }
}