// save subscriptions in tree structure // expose add, remove, findMatch methods //set of subscriberNode subscriptions

//Example of subscription topic: // status/${accountId}/collections/+/things/+/actions/#

// onTopicAdded - callback called when new topic is added to vault // onTopicRemoved - callback called when old topics no longer have subscribers and are removed from vault // Used for subscribing to external client topics // Only called once per topic, even if there are multiple subscribers

/**

• @class
• @name SubscriptionVault
• @classdesc Saves mqtt subscriptions in a tree structure by topic path.
• Example of message topic:

• status/myAccountId/collections/myCollection/things/myThingId/actions/myActionName

• Exposes these methods: add, remove, findMatches, reset
• @param {function} onTopicAdded - callback called when new topic is added to vault
• @param {function} onTopicRemoved - callback called when old topics no longer have subscribers and are removed from vault
• @example of subscriptionTree: { children: { status: { children: { myAccountId: { children: { collections: { children: { '#': { subscriptions: [callbackRef] } } } } } } } } } */