Address the comments

src/objective-c/GRPCClient/private/GRPCConnectivityMonitor.m

@@ -130,13 +130,7 @@ static void PassFlagsToContextInfoBlock(SCNetworkReachabilityRef target,
   if ((self = [super init])) {
     _reachabilityRef = CFRetain(reachability);
     _queue = dispatch_get_main_queue();
-    SCNetworkReachabilityFlags flags;
+    _previousReachabilityFlags = nil;
-    if (SCNetworkReachabilityGetFlags(_reachabilityRef, &flags)) {
-      _previousReachabilityFlags =
-          [[GRPCReachabilityFlags alloc] initWithFlags:flags];
-    } else {
-      _previousReachabilityFlags = 0;
-    }
   }
   return self;
 }
@@ -162,7 +156,8 @@ static void PassFlagsToContextInfoBlock(SCNetworkReachabilityRef target,
   [self startListeningWithHandler:^(GRPCReachabilityFlags *flags) {
     if (!flags.reachable) {
       handler();
-    } else if (flags.isWWAN ^ _previousReachabilityFlags.isWWAN) {
+    } else if (!_previousReachabilityFlags ||
+               (flags.isWWAN ^ _previousReachabilityFlags.isWAAN)) {
       wifiStatusChangeHandler();
     }
     _previousReachabilityFlags = flags;

src/objective-c/GRPCClient/private/GRPCHost.m

@@ -101,6 +101,9 @@ static GRPCConnectivityMonitor *connectivityMonitor = nil;
       _secure = YES;
       kHostCache[address] = self;
 
+      // When there is host in the cache, keep a single monitor to the network
+      // to
+      // flush the cache if the connectivity status changed
       if (!connectivityMonitor) {
         connectivityMonitor =
             [GRPCConnectivityMonitor monitorWithHost:hostURL.host];

src/objective-c/GRPCClient/private/GRPCReachabilityFlagNames.xmacro.h

@@ -55,7 +55,7 @@
 #endif
 
 #if TARGET_OS_IPHONE
-GRPC_XMACRO_ITEM(isCell, IsWWAN)
+GRPC_XMACRO_ITEM(isWWAN, IsWWAN)
 #endif
 GRPC_XMACRO_ITEM(reachable, Reachable)
 GRPC_XMACRO_ITEM(transientConnection, TransientConnection)
@@ -65,4 +65,3 @@ GRPC_XMACRO_ITEM(interventionRequired, InterventionRequired)
 GRPC_XMACRO_ITEM(connectionOnDemand, ConnectionOnDemand)
 GRPC_XMACRO_ITEM(isLocalAddress, IsLocalAddress)
 GRPC_XMACRO_ITEM(isDirect, IsDirect)
-GRPC_XMACRO_ITEM(isWWAN, IsWWAN)

src/objective-c/tests/Connectivity/Podfile

@@ -8,6 +8,7 @@ target 'ConnectivityTestingApp' do
   pod 'gRPC', :path => GRPC_LOCAL_SRC
   pod 'gRPC-Core', :path => GRPC_LOCAL_SRC
   pod 'gRPC-ProtoRPC', :path => GRPC_LOCAL_SRC
+  pod 'gRPC-RxLibrary', :path => GRPC_LOCAL_SRC
   pod 'Protobuf', :path => "#{GRPC_LOCAL_SRC}/third_party/protobuf"
   pod 'BoringSSL', :podspec => "#{GRPC_LOCAL_SRC}/src/objective-c"
 end