public static async Task<int> DeleteAsync<TEntity>(
            public static async Task<int> DeleteAsync<TEntity>(
            this DbContext context,
            Expression<Func<TEntity, bool>> predicate,
            CancellationToken cancellationToken = default(CancellationToken))
            where TEntity : class
        {
            var objectContext = ((IObjectContextAdapter)context).ObjectContext;
            var command = (ObjectQuery)objectContext.CreateObjectSet<TEntity>().Where(predicate).Select(o => new { });
            var querySql = command.ToTraceString();
            var deleteSql = "DELETE [Extent1] " + querySql.Substring(querySql.IndexOf("FROM"));
            var parameters = command.Parameters
                .Select(parameter => new SqlParameter(parameter.Name, parameter.Value))
                .Cast<object>();

            return await context.Database.ExecuteSqlCommandAsync(deleteSql, cancellationToken, parameters);
        }

        public static Task<int> DeleteAsync<TEntity, TKey>(
            this DbContext context,
            IEnumerable<TKey> ids,
            Expression<Func<TEntity, TKey>> idSelector,
            CancellationToken cancellationToken = default(CancellationToken))
            where TEntity : class
        {
        }