Partition a list into many partitions of equal size. Handy for things like migrations where you want to break things into "buckets"

LinqExtensions.Partition.cs

internal static class LinqExtensions
{
    public static List<List<T>> Partition<T>(this IEnumerable<T> list, int partitionSize)
    {
        var i = 0;
        var splits = from item in list
            group item by i++ / partitionSize into part
            select part.ToList();
        return splits.ToList();
    }
}