Bow Enchantment:(mineplex) Summoning/Barrage

If anyone remembers playing on Mineplex and taking a bow class, they usually have this ability for when you fully charge a bow, many arrows summon from it and rain upon your foes. This is an amazing sight to see, and being in the game itself would be nice.
Summoning is not compatible with infinity, punch 2 or power 4 or 5. It is however compatible with other bow enchantments.
Summoning 1: will summon 2 arrows.
Summoning 2: will summon 4 arrows.
Summoning 3: will summon 8 arrows.
This enchantment is not a treasure enchantment, however it is rare to find on the enchantment table, similar to silk touch.