added methods for connection headers updating

Sources/SwiftCentrifuge/Client.swift

@@ -217,6 +217,29 @@ public class CentrifugeClient {
         }
     }
 
+    /**
+     update(headers:) allows updating headers before next connect.
+     - parameter headers: [String: String]
+     */
+    public func update(headers: [String: String?]) {
+        self.syncQueue.async { [weak self] in
+            guard let strongSelf = self else { return }
+
+            if let conn = strongSelf.conn {
+                conn.update(headers: headers)
+            } else {
+                for (key, value) in headers {
+                    guard let value else {
+                        strongSelf.config.headers.removeValue(forKey: key)
+                        continue
+                    }
+                    strongSelf.config.headers[key] = value
+                }
+            }
+        }
+    }
+
+
     /**
      Create subscription object to specific channel with delegate
      - parameter channel: String

Sources/SwiftCentrifuge/WebSocket/NativeWebSocket.swift

@@ -22,7 +22,7 @@ final class NativeWebSocket: NSObject, WebSocketInterface, URLSessionWebSocketDe
     private var session: URLSession?
 
     private let log: CentrifugeLogger
-    private let request: URLRequest
+    private var request: URLRequest //this is only to allow headers, timeout, etc to be modified on reconnect
     private let queue: DispatchQueue
 
     /// The websocket is considered 'active' when `task` is not nil
@@ -76,6 +76,12 @@ final class NativeWebSocket: NSObject, WebSocketInterface, URLSessionWebSocketDe
         })
     }
 
+    func update(headers: [String : String?]) {
+        for (key, value) in headers {
+            self.request.setValue(value, forHTTPHeaderField: key)
+        }
+    }
+
     private func doRead() {
         task?.receive { [weak self] (result) in
             guard let self = self else { return }

Sources/SwiftCentrifuge/WebSocket/StarscreamWebSocket.swift

@@ -44,6 +44,12 @@ final class StarscreamWebSocket: WebSocketInterface {
         socket.write(data: data)
     }
 
+    func update(headers: [String : String?]) {
+        for (key, value) in headers {
+            self.socket.request.setValue(value, forHTTPHeaderField: key)
+        }
+    }
+
     private func setup() {
         socket.onConnect = { [weak self] in
             self?.onConnect?()

Sources/SwiftCentrifuge/WebSocket/WebSocketInterface.swift

@@ -13,6 +13,8 @@ protocol WebSocketInterface: AnyObject {
     var onDisconnect: ((CentrifugeDisconnectOptions, Error?) -> Void)? { get set }
     var onData: ((Data) -> Void)? { get set }
 
+    func update(headers: [String: String?])
+
     func connect()
     func disconnect()
     func write(data: Data)