simple mongodb repository implementation

Repository.cs

public class Repository<TEntity> : IRepository<TEntity>
{
    private readonly IMongoCollection<TEntity> _collection;

    public Repository(IMongoCollection<TEntity> collection)
    {
        if (null == collection)
            throw new ArgumentNullException("collection");
        _collection = collection;

        this.CollectionName = collection.CollectionNamespace.CollectionName;
    }

    public string CollectionName { get; private set; }

    public Task<long> CountAsync(FilterDefinition<TEntity> filter)
    {
        return _collection.CountAsync(filter);
    }

    public IFindFluent<TEntity, TEntity> Find(FilterDefinition<TEntity> filter)
    {
        return _collection.Find(filter);
    }
    public IFindFluent<TEntity, TEntity> Find(Expression<Func<TEntity, bool>> filter)
    {
        return _collection.Find(filter);
    }

    public Task<TEntity> FindOneAndReplaceAsync(FilterDefinition<TEntity> filter, TEntity replacement)
    {
        return _collection.FindOneAndReplaceAsync(filter, replacement);
    }
    public Task<TEntity> FindOneAndReplaceAsync(Expression<Func<TEntity, bool>> filter, TEntity replacement)
    {
        return _collection.FindOneAndReplaceAsync(filter, replacement);
    }
}