Returns an Aggregator that selects the first instance of T in the aggregated stream.
Returns a Semigroup instance with a plus implementation that always returns the first (ie, the
left) T argument.
Returns a Semigroup instance with a plus implementation that always returns the first (ie, the
left) T argument.
This semigroup's sumOption is efficient; it only selects the head of the TraversableOnce instance,
leaving the rest untouched.
Provides a set of operations and typeclass instances needed to use First instances.