Resample the series based on a provided collection of keys. The values of the series are aggregated into chunks based on the specified keys. Depending on `direction`, the specified key is either used as the smallest or as the greatest key of the chunk (with the exception of boundaries that are added to the first/last chunk). Such chunks are then returned as nested series. ## Parameters - `series` - An input series to be resampled - `keys` - A collection of keys to be used for resampling of the series - `dir` - If this parameter is `Direction.Forward`, then each key is used as the smallest key in a chunk; for `Direction.Backward`, the keys are used as the greatest keys in a chunk. ## Remarks This operation is only supported on ordered series. The method throws `InvalidOperationException` when the series is not ordered. [category:Sampling, resampling and advanced lookup]

public static Series<K, Series<K, V>> resample<K, V>(
	IEnumerable<K> keys,
	Direction dir,
	Series<K, V> series
)