open func addObserver(_ observer: Any, selector aSelector: Selector, name aName: NSNotification.Name?, object anObject: Any?)

func onReceivedNotification(note: NSNotification)

open func post(name aName: NSNotification.Name, object anObject: Any?, userInfo aUserInfo: [AnyHashable : Any]? = nil)

open func removeObserver(_ observer: Any, name aName: NSNotification.Name?, object anObject: Any?)

open func addObserver(forName name: NSNotification.Name?, object obj: Any?, queue: OperationQueue?, using block: @escaping (Notification) -> Void) -> NSObjectProtocol

open class NSNotification : NSObject, NSCopying, NSCoding {
  open var name: NSNotification.Name { get }
  open var object: Any? { get }
  open var userInfo: [AnyHashable : Any]? { get }
}

let following = notification.userInfo["FollowingKey"] as! NSNumber
let userID = notification.userInfo["UserIDKey"] as! NSNumber;

protocol FollowingChanged {
  func followingDidChange(following: Bool, userID: NSNumber)
}

Broadcaster.register(Update.self, observer: observer)

extension ViewController: FollowingChanged {
 func followingDidChange(following: Bool, userID: NSNumber) {
  // do something
 }
}

Broadcaster.notify(FollowingChanged.self) {
  $0.followingDidChange(following, userID)
}

Broadcaster.unregister(Update.self, observer: observer)

protocol FollowingChanging {
  func followingDidChange(following: Bool, userID: NSNumber, followingEachOther: NSNumber?)
}

 class TPFollowingChangedEvent: NSObject, TPEvent {
  	private(set) var following: Bool
  		private(set) var userID: NSNumber
}

TPEventBus<TPFollowingChangedEvent>.shared.register(eventType: TPFollowingChangedEvent.self, subscriber: self, selector: #selector(onEvent(event:object:)))

@objc func onEvent(event: TPFollowingChangedEvent, object: Any?) {
  	// do something
}

TPEventBus.shared.post(event: event, object: self)

TPEventBus<TPFollowingChangedEvent>.shared.unregister(eventType: TPFollowingChangedEvent.self, subscriber: self)

class TPFollowingChangedEvent: NSObject, TPEvent {
  	private(set) var following: Bool
  		private(set) var userID: NSNumber
  	private(set) var followingEachOther: NSNumber?
}

TPEventBus<TPFollowingChangedEvent>.shared.subscribe(eventType: TPFollowingChangedEvent.self).forObject(self).onQueue(OperationQueue.main).onEvent { (event, object) in
   // do something
}.disposed(by: self)