Specify which interface to use for transport?

[emmanuelproulx]

Is there a way to choose which interface to use for the MQTT connection?
I'm talking about the InterfaceType: https://developer.apple.com/documentation/network/nwinterface/interfacetype

I want to force the client to use the .wifi interface but it goes to the .cellular interface (probably because there's no Internet available on my .wifi network -- this is on purpose as I need to connect to a local device).

If this can't be done, please put it in the wishlist.

[emmanuelproulx]

I'm thinking something like this, with new Configuration.interfaceType item of type NWInterface.InterfaceType (can be nil):

    static func getBootstrap(client: MQTTClient) throws -> NIOClientTCPBootstrap {
        var bootstrap: NIOClientTCPBootstrap
        let serverName = client.configuration.sniServerName ?? client.host
        #if canImport(Network)
        // if eventLoop is compatible with NIOTransportServices create a NIOTSConnectionBootstrap
        if #available(OSX 10.14, iOS 12.0, tvOS 12.0, watchOS 6.0, *),
            let tsBootstrap = NIOTSConnectionBootstrap(validatingGroup: client.eventLoopGroup)
        {
            if let type = client.configuration.interfaceType {
                tsBootstrap.configureNWParameters { params in
                    params.requiredInterfaceType = type
                }
            }