Update closeConnection function

 - Invalidate ping timer and update isConnected property.

Sources/ObservableWebSocketClient/Interface/ObservableWebSocketClient+Connection.swift

@@ -11,12 +11,16 @@ public extension ObservableWebSocketClient {
 
     /// Sends a close frame with an optional close reason.
     ///
+    /// This function also invalidates the `pingTimerInterval`, if any.
+    ///
     /// - Parameter closeCode: A `URLSessionWebSocketTask.CloseCode`
     /// that indicates the reason for closing the connection. The default is `.normalClosure`.
     /// - Parameter reason: Optional further information to explain the closing.
     /// The value of this parameter is defined by the endpoints, not by the standard.
     func closeConnection(with closeCode: URLSessionWebSocketTask.CloseCode = .normalClosure,
                          reason: String? = nil) {
+        pingTimer?.invalidate()
         service.close(reason: reason)
+        isConnected = false
     }
 }

Sources/ObservableWebSocketClient/Interface/ObservableWebSocketClient.swift

@@ -26,7 +26,7 @@ public final class ObservableWebSocketClient: Identifiable, Equatable, Codable,
 
     public let websocketURL: URL
 
-    private var pingTimer: Timer?
+    private(set) var pingTimer: Timer?
     private let pingTimerInterval: TimeInterval?
     private let pingMessage: String?
     private let pingMessageWithGeneratedId: ((String) -> String)?
@@ -93,8 +93,7 @@ public final class ObservableWebSocketClient: Identifiable, Equatable, Codable,
     }
 
     deinit {
-        pingTimer?.invalidate()
-        service.close()
+        closeConnection()
     }
 }