feature: completion added to start function

Author: anik-appnap

SwifterExample/main.swift

@@ -15,7 +15,7 @@ server["/files/:path"] = directoryBrowser("/")
 
 let semaphore = DispatchSemaphore(value: 0)
 do {
-  try server.start(9080, forceIPv4: true)
+    try server.start(9080, forceIPv4: true){_ in}
   print("Server has started ( port = \(try server.port()) ). Try to connect now...")
   semaphore.wait()
 } catch {

Xcode/Sources/HttpServerIO.swift

@@ -68,13 +68,14 @@ open class HttpServerIO {
     }
 
     @available(macOS 10.10, *)
-    public func start(_ port: in_port_t = 8080, forceIPv4: Bool = false, priority: DispatchQoS.QoSClass = DispatchQoS.QoSClass.background) throws {
+    public func start(_ port: in_port_t = 8080, forceIPv4: Bool = false, priority: DispatchQoS.QoSClass = DispatchQoS.QoSClass.background, completion: (Bool) -> ()) throws {
         guard !self.operating else { return }
         stop()
         self.state = .starting
         let address = forceIPv4 ? listenAddressIPv4 : listenAddressIPv6
         self.socket = try Socket.tcpSocketForListen(port, forceIPv4, SOMAXCONN, address)
         self.state = .running
+        completion(true)
         DispatchQueue.global(qos: priority).async { [weak self] in
             guard let strongSelf = self else { return }
             guard strongSelf.operating else { return }