swift OutputStream delegate issue

test.swift

import Foundation

class TestClass: NSObject, StreamDelegate {
    
    func stream(_ aStream: Stream, handle eventCode: Stream.Event) {
        print("FOO")
    }
    
    func main() {
        let profile = "<amin:command name='mkdir' xmlns:amin='http://projectamin.org/ns/'>\n\t<amin:flag name='m'>0755</amin:flag>\n\t<amin:param name=\"target\">/tmp/test_ashell</amin:param>\n</amin:command>"


        // Testing delegate

        let testStream = OutputStream.toMemory()
        testStream.schedule(in: RunLoop.current, forMode: RunLoop.Mode.default)
        testStream.delegate = self
        testStream.open()
        let xmlByteArray = [UInt8](profile.utf8)
        testStream.write(xmlByteArray, maxLength: xmlByteArray.count)
        testStream.close()
        
        let outputData = testStream.property(forKey: Stream.PropertyKey.dataWrittenToMemoryStreamKey) as! Data
        let outputBytes = [UInt8](outputData)
        let outputXml = String(decoding: outputBytes, as: UTF8.self)
        print(outputXml)
    }
}

print("Launching stream test app")
let foo = TestClass()
foo.main()