Nil check our run loop thread (#771) (#772)

* Update RCTCxxBridge.mm

* Update RCTCxxBridge.mm

* run loop nil check

Co-authored-by: Chris Hogan <[email protected]>

Co-authored-by: Chris Hogan <[email protected]>

Author: HeyImChris

Libraries/WebSocket/RCTSRWebSocket.m

@@ -530,7 +530,14 @@ - (void)_initializeStreams
 - (void)_connect
 {
   if (!_scheduledRunloops.count) {
-    [self scheduleInRunLoop:[NSRunLoop RCTSR_networkRunLoop] forMode:NSDefaultRunLoopMode];
+    // [TODO(macOS ISS#2323203): `scheduleInRunLoop:forMode:` takes in a non-null run loop parameter so let's be safe and verify that
+    NSRunLoop *runLoop = [NSRunLoop RCTSR_networkRunLoop];
+    if (runLoop != nil) {
+      [self scheduleInRunLoop:runLoop forMode:NSDefaultRunLoopMode];
+    } else {
+      RCTSRLog(@"Failed connecting to RCTSR_networkRunLoop");
+    }
+    // ]TODO(macOS ISS#2323203)
   }
 
   [_outputStream open];