[RUM-9753] Fix crash when calling eventEmitter.sendEvent with invalid bridge after Fast Refresh

packages/core/ios/Sources/DdSdk.h

@@ -24,5 +24,6 @@
 @property(nonatomic, strong) DdSdkImplementation *ddSdkImplementation;
 
 + (void)initFromNative;
++ (RCTBridge * _Nullable)latestBridgeReference;
 
 @end

packages/core/ios/Sources/DdSdk.mm

@@ -14,7 +14,12 @@
 
 @implementation DdSdk
 
-@synthesize bridge = _bridge;
+static __weak RCTBridge *s_latestBridge = nil;
+
++ (RCTBridge *)latestBridgeReference {
+    return s_latestBridge;
+}
+
 RCT_EXPORT_MODULE()
 
 RCT_REMAP_METHOD(initialize, withConfiguration:(NSDictionary*)configuration
@@ -105,7 +110,8 @@ @implementation DdSdk
 - (DdSdkImplementation*)ddSdkImplementation
 {
     if (_ddSdkImplementation == nil) {
-        _ddSdkImplementation = [[DdSdkImplementation alloc] initWithBridge:_bridge];
+        s_latestBridge = self.bridge;
+        _ddSdkImplementation = [[DdSdkImplementation alloc] initWithBridge:self.bridge];
     }
     return _ddSdkImplementation;
 }

packages/core/ios/Sources/DdSdkNativeInitialization.swift

@@ -151,7 +151,18 @@ public class DdSdkNativeInitialization: NSObject {
             }
         }
         let onSessionStart: RUM.SessionListener = { sessionId, isDiscarded in
-            let body: [String: Any?] = ["sessionId": sessionId, "isDiscarded": isDiscarded]
+            guard
+                let emitter = eventEmitter,
+                let bridge = emitter.bridge,
+                let latestBridge = DdSdk.latestBridgeReference(),
+                bridge === latestBridge
+            else {
+                return
+            }
+
+            let body: [String: Any?] = [
+                "sessionId": sessionId, "isDiscarded": isDiscarded,
+            ]
             eventEmitter?.sendEvent(withName: "RumSessionStarted", body: body)
         }