Swift 使用AVFoundation和AVAudioNode如何获取一个音频源并将其路由到多个目的地？

我正在尝试做一些理论上应该非常简单的事情，即从单个AVAudioNode产生的音频，并将其路由到多个输出，这些输出也是AVAudioNode。但是，我没有看到这样的类。这本质上类似于拆分器对象

我想这样做：

import AVFoundation
class Router{
func connect(){
        let node1 = mixerNode()
        let node2 = mixerNode()
        let node3 = mixerNode()
        let engine = AVAudioEngine()
        let format = node1.outputFormat(forBus: 0)
        engine.attach(node1)
        engine.attach(node2)
        engine.attach(node3)
        engine.connect(node1, to: node2, format: format)
        engine.connect(node1, to: node3, format: format)
        let connections = engine.outputConnectionPoints(for: node1, outputBus: 0)
        print("Num connections = \(connections.count)")
}

   import AVFoundation
   class someClass{ 
        func connectMultipleNodes(){
            let engine = AVAudioEngine()
            let node1 = AVAudioNode()
            let node2 = AVAudioNode()
            let node3 = AVAudioNode()
            engine.attach(node1)
            engine.attach(node2)
            engine.attach(node3)
            let format = node1.outputFormat(forBus: 0)
            let connection1 = AVAudioConnectionPoint(node: node2, bus: 0)
            let connection2 = AVAudioConnectionPoint(node: node3, bus: 0)
            let connections = [connection1, connection2]
            engine.connect(node1, to: connections, fromBus: 0, format: format)
       }
   }

---

但是，控制台显示node1仅连接到一个节点，因为它只能有一个输出。有允许多个输出的对象吗？

我知道怎么做了。没有“拆分器”节点。但是，AVAudioEngine允许您使用AVAudioConnection将任何一个节点路由到多个输出目的地，如下所示：

import AVFoundation
class Router{
func connect(){
        let node1 = mixerNode()
        let node2 = mixerNode()
        let node3 = mixerNode()
        let engine = AVAudioEngine()
        let format = node1.outputFormat(forBus: 0)
        engine.attach(node1)
        engine.attach(node2)
        engine.attach(node3)
        engine.connect(node1, to: node2, format: format)
        engine.connect(node1, to: node3, format: format)
        let connections = engine.outputConnectionPoints(for: node1, outputBus: 0)
        print("Num connections = \(connections.count)")
}

   import AVFoundation
   class someClass{ 
        func connectMultipleNodes(){
            let engine = AVAudioEngine()
            let node1 = AVAudioNode()
            let node2 = AVAudioNode()
            let node3 = AVAudioNode()
            engine.attach(node1)
            engine.attach(node2)
            engine.attach(node3)
            let format = node1.outputFormat(forBus: 0)
            let connection1 = AVAudioConnectionPoint(node: node2, bus: 0)
            let connection2 = AVAudioConnectionPoint(node: node3, bus: 0)
            let connections = [connection1, connection2]
            engine.connect(node1, to: connections, fromBus: 0, format: format)
       }
   }