Partition
A single group produced by a PartitionBy expression. Holds the partition key value and the list of source elements that share it. Authors read `key` and `members` off Partition embeddeds when iterating the PartitionBy result.
A single group produced by a PartitionBy expression. Holds the partition key value and the list of source elements that share it. Authors read `key` and `members` off Partition embeddeds when iterating the PartitionBy result.
