GetPostsAsync.cs

public async Task<List<Post>> GetPostsAsync(PaginationFilter paginationFilter = null)
{
    if (paginationFilter == null)
    {
        return await _dataContext.Posts.Include(x => x.Tags).ToListAsync();
    }

    var skip = (paginationFilter.PageNumber - 1) * paginationFilter.PageSize;
    return await _dataContext.Posts.Include(x => x.Tags)
        .Skip(skip).Take(paginationFilter.PageSize).ToListAsync();
}