clean up emit completion code

Source/SocketIO/Client/SocketIOClient.swift

@@ -213,7 +213,7 @@ open class SocketIOClient : NSObject, SocketIOClientSpec {
     /// - parameter items: The items to send with this event. May be left out.
     open func emit(_ event: String, _ items: SocketData...) {
         do {
-            try emit(event, with: items.map({ try $0.socketRepresentation() }), completion: {})
+            try emit(event, with: items.map({ try $0.socketRepresentation() }))
         } catch {
             DefaultSocketLogger.Logger.error("Error creating socketRepresentation for emit: \(event), \(items)",
                                              type: logType)
@@ -247,7 +247,7 @@ open class SocketIOClient : NSObject, SocketIOClientSpec {
     /// - parameter items: The items to send with this event. Send an empty array to send no data.
     @objc
     open func emit(_ event: String, with items: [Any]) {
-        emit([event] + items, completion: {})
+        emit([event] + items)
     }
 
     /// Same as emit, but meant for Objective-C
@@ -313,15 +313,22 @@ open class SocketIOClient : NSObject, SocketIOClientSpec {
         return createOnAck([event] + items)
     }
 
-    func emit(_ data: [Any], ack: Int? = nil, binary: Bool = true, isAck: Bool = false, completion: (() -> ())? = nil) {
+    func emit(_ data: [Any],
+              ack: Int? = nil,
+              binary: Bool = true,
+              isAck: Bool = false,
+              completion: @escaping () -> () = {}
+    ) {
         // wrap the completion handler so it always runs async via handlerQueue
         let wrappedCompletion = {[weak self] in
             guard let this = self else { return }
-            this.manager?.handleQueue.async { completion?() }
+            this.manager?.handleQueue.async {
+                completion()
+            }
         }
 
         guard status == .connected else {
-            wrappedCompletion();
+            wrappedCompletion()
             handleClientEvent(.error, data: ["Tried emitting when not connected"])
             return
         }
@@ -331,7 +338,7 @@ open class SocketIOClient : NSObject, SocketIOClientSpec {
 
         DefaultSocketLogger.Logger.log("Emitting: \(str), Ack: \(isAck)", type: logType)
 
-        manager?.engine?.send(str, withData: packet.binary, completion: completion != nil ? wrappedCompletion : nil)
+        manager?.engine?.send(str, withData: packet.binary, completion: wrappedCompletion)
     }
 
     /// Call when you wish to tell the server that you've received the event for `ack`.

Source/SocketIO/Engine/SocketEnginePollable.swift

@@ -226,8 +226,6 @@ extension SocketEnginePollable {
 
         for data in datas {
             if case let .right(bin) = createBinaryDataForSend(using: data) {
-                // completion handler will be called on initial message write
-                //     TODO: call completion after last message in batch
                 postWait.append((bin, {}))
             }
         }

Source/SocketIO/Engine/SocketEngineSpec.swift

@@ -180,7 +180,7 @@ extension SocketEngineSpec {
     }
 
     /// Send an engine message (4)
-    func send(_ msg: String, withData datas: [Data], completion: (() -> ())? = nil) {
+    func send(_ msg: String, withData datas: [Data], completion: @escaping () -> () = {}) {
-        write(msg, withType: .message, withData: datas, completion: completion ?? {})
+        write(msg, withType: .message, withData: datas, completion: completion)
     }
 }

Source/SocketIO/Engine/SocketEngineWebsocket.swift

@@ -38,7 +38,10 @@ public protocol SocketEngineWebsocket : SocketEngineSpec {
     /// - parameter withType: The type of message to send.
     /// - parameter withData: The data associated with this message.
     /// - parameter completion: Callback called on transport write completion.
-    func sendWebSocketMessage(_ str: String, withType type: SocketEnginePacketType, withData datas: [Data], completion: @escaping () -> ())
+    func sendWebSocketMessage(_ str: String,
+                              withType type: SocketEnginePacketType,
+                              withData datas: [Data],
+                              completion: @escaping () -> ())
 }
 
 // WebSocket methods
@@ -57,7 +60,11 @@ extension SocketEngineWebsocket {
     /// - parameter withType: The type of message to send.
     /// - parameter withData: The data associated with this message.
     /// - parameter completion: Callback called on transport write completion.
-    public func sendWebSocketMessage(_ str: String, withType type: SocketEnginePacketType, withData datas: [Data], completion: @escaping () -> ()) {
+    public func sendWebSocketMessage(_ str: String,
+                                     withType type: SocketEnginePacketType,
+                                     withData datas: [Data],
+                                     completion: @escaping () -> ()
+    ) {
         DefaultSocketLogger.Logger.log("Sending ws: \(str) as type: \(type.rawValue)", type: "SocketEngineWebSocket")
 
         ws?.write(string: "\(type.rawValue)\(str)")