Replace `each` with event symbol

Changed

• Make each its own event using symbols f147652

v2.0.1...v3.0.0

Use sets

Added

• Use unknown for valid args type 9fea103
• Replace callback array with Set 0af5fdd

Fixed

• Remove old tinyevents name 3325211

v2.0.0...v2.0.1

Return `off` function directly

Changed

• Remove off function directly from on 7dee8dc

v1.0.0...v2.0.0

Initial Release

Pulled out from servie core since it's a type-safe and tiny event emitter I'd like to use in other places.