diff --git a/Source/WebSocket.swift b/Source/WebSocket.swift
index ca0ebe27..a436d786 100644
--- a/Source/WebSocket.swift
+++ b/Source/WebSocket.swift
@@ -372,9 +372,12 @@ open class WebSocket : NSObject, StreamDelegate {
         
         let bytes = UnsafeRawPointer((data as NSData).bytes).assumingMemoryBound(to: UInt8.self)
         var out = timeout * 1_000_000 // wait 5 seconds before giving up
-        writeQueue.addOperation { [weak self] in
-            while !outStream.hasSpaceAvailable {
+        let operation = BlockOperation()
+        operation.addExecutionBlock { [weak self, weak operation] in
+            guard let sOperation = operation else { return }
+            while !outStream.hasSpaceAvailable && !sOperation.isCancelled {
                 usleep(100) // wait until the socket is ready
+                guard !sOperation.isCancelled else { return }
                 out -= 100
                 if out < 0 {
                     self?.cleanupStream()
@@ -384,8 +387,10 @@ open class WebSocket : NSObject, StreamDelegate {
                     return // disconnectStream will be called.
                 }
             }
+            guard !sOperation.isCancelled else { return }
             outStream.write(bytes, maxLength: data.count)
         }
+        writeQueue.addOperation(operation)
     }
     
     /**
@@ -840,9 +845,11 @@ open class WebSocket : NSObject, StreamDelegate {
      Used to write things to the stream
      */
     private func dequeueWrite(_ data: Data, code: OpCode, writeCompletion: (() -> ())? = nil) {
-        writeQueue.addOperation { [weak self] in
+        let operation = BlockOperation()
+        operation.addExecutionBlock { [weak self, weak operation] in
             //stream isn't ready, let's wait
             guard let s = self else { return }
+            guard let sOperation = operation else { return }
             var offset = 2
             let dataLength = data.count
             let frame = NSMutableData(capacity: dataLength + s.MaxFrameSize)
@@ -869,7 +876,7 @@ open class WebSocket : NSObject, StreamDelegate {
                 offset += 1
             }
             var total = 0
-            while true {
+            while !sOperation.isCancelled {
                 guard let outStream = s.outputStream else { break }
                 let writeBuffer = UnsafeRawPointer(frame!.bytes+total).assumingMemoryBound(to: UInt8.self)
                 let len = outStream.write(writeBuffer, maxLength: offset-total)
@@ -896,8 +903,8 @@ open class WebSocket : NSObject, StreamDelegate {
                     break
                 }
             }
-
         }
+        writeQueue.addOperation(operation)
     }
     
     /**