Splits a single PCollection of objects, with keys k, into an object of
PCollections, with the same keys k, where each PCollection consists of the
values associated with that key. That is,
PCollection<{a: T, b: U, ...}> maps to {a: PCollection<T>, b: PCollection<U>, ...}
Splits a single PCollection of objects, with keys k, into an object of PCollections, with the same keys k, where each PCollection consists of the values associated with that key. That is,
PCollection<{a: T, b: U, ...}>maps to{a: PCollection<T>, b: PCollection<U>, ...}