Merge "Wait for IpClient.StoppedState#enter before tests" into rvc-dev am: b91dc822

        mNetworkObserverRegistry.register(mNetd);

        mIpc = new IpClient(mContext, mIfaceName, mCb, mNetworkObserverRegistry,

                mNetworkStackServiceManager, mDependencies);

        // Wait for IpClient to enter its initial state. Otherwise, additional setup steps or tests

        // that mock IpClient's dependencies might interact with those mocks while IpClient is

        // starting. This would cause UnfinishedStubbingExceptions as mocks cannot be interacted

        // with while they are being stubbed.

        HandlerUtilsKt.waitForIdle(mIpc.getHandler(), TEST_TIMEOUT_MS);

        // Tell the IpMemoryStore immediately to answer any question about network attributes with a

        // null response. Otherwise, the DHCP client will wait for two seconds before starting,