Interface Ds\Collection

`extends`	`Countable, IteratorAggregate, JsonSerializable`

Collection is the base interface which covers functionality common to all the data structures in this library. It guarantees that all structures are traversable, countable, and can be converted to json using json_encode().

Ds\Collection extends Countable, IteratorAggregate, JsonSerializable
- Ds\Map implements Collection
- Ds\Set implements Collection
- Ds\Stack implements Collection
- Ds\Queue implements Collection
- Ds\PriorityQueue implements Collection
- Ds\Sequence extends Collection
  - Ds\Vector implements Sequence
  - Ds\Deque implements Sequence

Methods
`public`	`clear(): void` Removes all values from the collection. Removes all values from the collection. Implemented by `Ds\Vector::clear()` `Ds\Deque::clear()` `Ds\Map::clear()` `Ds\Set::clear()` `Ds\Stack::clear()` `Ds\Queue::clear()` `Ds\PriorityQueue::clear()`	#
`public`	`copy(): Collection` Returns a shallow copy of the collection. Returns a shallow copy of the collection. Implemented by `Ds\Vector::copy()` `Ds\Deque::copy()` `Ds\Map::copy()` `Ds\Set::copy()` `Ds\Stack::copy()` `Ds\Queue::copy()` `Ds\PriorityQueue::copy()`	#
`public`	`isEmpty(): bool` Returns whether the collection is empty. Returns whether the collection is empty. Implemented by `Ds\Vector::isEmpty()` `Ds\Deque::isEmpty()` `Ds\Map::isEmpty()` `Ds\Set::isEmpty()` `Ds\Stack::isEmpty()` `Ds\Queue::isEmpty()` `Ds\PriorityQueue::isEmpty()`	#
`public`	`toArray(): array` Converts the collection to an array. <p><b>Note:</b> Casting to an array is not supported yet.</p> Converts the collection to an array. Note: Casting to an array is not supported yet. Returns An array containing all the values in the same order as the collection. Implemented by `Ds\Vector::toArray()` `Ds\Deque::toArray()` `Ds\Map::toArray()` `Ds\Set::toArray()` `Ds\Stack::toArray()` `Ds\Queue::toArray()` `Ds\PriorityQueue::toArray()`	#

Methods inherited from Countable
`count()`

Methods inherited from IteratorAggregate
`getIterator()`

Methods inherited from JsonSerializable
`jsonSerialize()`