Open Radar

 
Simulator for iPhone and VisionOS (and probably all the rest too) ignore `NWParemeters.requiredLocalEndpoint` and instead chooses a random outbound port. Real devices respect this parameter and choose the assigned local bound port.

Here’s the code that sets the `requiredLocalEndpoint`.

```
let remoteRtcpEndpoint = NWEndpoint.hostPort(host: NWEndpoint.Host(remoteRTCPAddress), port: NWEndpoint.Port(rawValue: 5150re)!)

let rtcpParameters = NWParameters.udp
let localEndpoint = NWEndpoint.hostPort(host: NWEndpoint.Host("0.0.0.0"), port: NWEndpoint.Port(rawValue: 6970)!)
Self.logger.info("Starting rtcp with local port \(6970), remote address \(5150), endpoint \(String(describing: localEndpoint))")
rtcpParameters.requiredLocalEndpoint = localEndpoint
rtcpParameters.allowLocalEndpointReuse = true

remoteRtcpConnection = NWConnection(to: remoteRtcpEndpoint, using: rtcpParameters)
remoteRtcpConnection.start(queue: .global())
```

And here's the code that sends the payload

```
            remoteRtcpConnection.send(content: RtcpPacket.vdly(delayMs: HUGE_FIXED_VDLY_MS).packet(), completion: .contentProcessed({ error in
                if let error = error {
                    Self.logger.warning("Error sending VDLY packet \(error)")
                    continuation.resume(throwing: error)
                } else {
                    Self.logger.debug("VDLY Sent \(self.HUGE_FIXED_VDLY_MS)")
                    continuation.resume(returning: ())
                }
            }))
```

Expected Behavior:
- A UDP packet is sent from local port 6970 to remote port 5150 on all devices and simulators

iPhone and MacOS Real Device Behavior (Working):
- A UDP packet is sent from local port 6970 to remote port 5150

iOS and VisionOS Simulator Device Behavior (Not working):
- A UDP packet is sent from a random local port to remote port 5150