diff --git a/AFNetworking/AFURLConnectionOperation.m b/AFNetworking/AFURLConnectionOperation.m
index e1c0a4b..6f4838e 100644
--- a/AFNetworking/AFURLConnectionOperation.m
+++ b/AFNetworking/AFURLConnectionOperation.m
@@ -253,6 +253,10 @@ static inline BOOL AFStateTransitionIsValid(AFOperationState fromState, AFOperat
 }
 
 - (void)setOutputStream:(NSOutputStream *)outputStream {
+    if (outputStream == _outputStream) {
+        return;
+    }
+    
     [self willChangeValueForKey:@"outputStream"];
     [outputStream retain];
     
@@ -262,11 +266,6 @@ static inline BOOL AFStateTransitionIsValid(AFOperationState fromState, AFOperat
     }
     _outputStream = outputStream;
     [self didChangeValueForKey:@"outputStream"];
-    
-    NSRunLoop *runLoop = [NSRunLoop currentRunLoop];
-    for (NSString *runLoopMode in self.runLoopModes) {
-        [self.outputStream scheduleInRunLoop:runLoop forMode:runLoopMode];
-    }
 }
 
 #if __IPHONE_OS_VERSION_MIN_REQUIRED