Changed timeout timer from NSTimer to GCD timer to avoid retain cycle.

SocketIO.h

@@ -79,7 +79,7 @@ typedef enum {
 
     // heartbeat
     NSTimeInterval _heartbeatTimeout;
-    NSTimer *_timeout;
+    dispatch_source_t _timeout;
 
     NSMutableArray *_queue;
 

SocketIO.m

@@ -359,6 +359,11 @@ - (void) removeAcknowledgeForKey:(NSString *)key
 
 - (void) onTimeout 
 {
+    if (_timeout) {
+        dispatch_source_cancel(_timeout);
+        _timeout = NULL;
+    }
+
     DEBUGLOG(@"Timed out waiting for heartbeat.");
     [self onDisconnect:[NSError errorWithDomain:SocketIOError
                                            code:SocketIOHeartbeatTimeout
@@ -368,16 +373,29 @@ - (void) onTimeout
 - (void) setTimeout 
 {
     DEBUGLOG(@"start/reset timeout");
-    if (_timeout != nil) {
-        [_timeout invalidate];
-        _timeout = nil;
+    if (_timeout) {
+        dispatch_source_cancel(_timeout);
+        _timeout = NULL;
     }
 
-    _timeout = [NSTimer scheduledTimerWithTimeInterval:_heartbeatTimeout
-                                                target:self 
-                                              selector:@selector(onTimeout) 
-                                              userInfo:nil 
-                                               repeats:NO];
+    _timeout = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER,
+                                      0,
+                                      0,
+                                      dispatch_get_main_queue());
+
+    dispatch_source_set_timer(_timeout,
+                              dispatch_time(DISPATCH_TIME_NOW, _heartbeatTimeout * NSEC_PER_SEC),
+                              0,
+                              0);
+
+    __weak SocketIO *weakSelf = self;
+
+    dispatch_source_set_event_handler(_timeout, ^{
+        [weakSelf onTimeout];
+    });
+
+    dispatch_resume(_timeout);
+
 }
 
 
@@ -556,9 +574,9 @@ - (void) onDisconnect:(NSError *)error
     [_queue removeAllObjects];
 
     // Kill the heartbeat timer
-    if (_timeout != nil) {
-        [_timeout invalidate];
-        _timeout = nil;
+    if (_timeout) {
+        dispatch_source_cancel(_timeout);
+        _timeout = NULL;
     }
 
     // Disconnect the websocket, just in case
@@ -768,8 +786,10 @@ - (void) dealloc
 
     _transport = nil;
 
-    [_timeout invalidate];
-    _timeout = nil;
+    if (_timeout) {
+        dispatch_source_cancel(_timeout);
+        _timeout = NULL;
+    }
 
     _queue = nil;
     _acks = nil;