Implements Drupal\Core\KeyValueStore\KeyValueStoreInterface::set().
Overrides KeyValueStoreInterface::set
public function set($key, $value) {
$this->connection
->merge($this->table)
->key(array(
'name' => $key,
'collection' => $this->collection,
))
->fields(array(
'value' => serialize($value),
))
->execute();
}