Timestamps and Failed to resolve name Error

Following error are coming when run this project.

dependencies using as follows.
cloud_firestore: ^0.8.2

```
W/Firestore(29258): (0.6.6-dev) [Firestore]: The behavior for java.util.Date objects stored in Firestore is going to change AND YOUR APP MAY BREAK.
W/Firestore(29258): To hide this warning and ensure your app does not break, you need to add the following code to your app before calling any other Cloud Firestore methods:
W/Firestore(29258):
W/Firestore(29258): FirebaseFirestore firestore = FirebaseFirestore.getInstance();
W/Firestore(29258): FirebaseFirestoreSettings settings = new FirebaseFirestoreSettings.Builder()
W/Firestore(29258): .setTimestampsInSnapshotsEnabled(true)
W/Firestore(29258): .build();
W/Firestore(29258): firestore.setFirestoreSettings(settings);
W/Firestore(29258):
W/Firestore(29258): With this change, timestamps stored in Cloud Firestore will be read back as com.google.firebase.Timestamp objects instead of as system java.util.Date objects. So you will also need to update code expecting a java.util.Date to instead expect a Timestamp. For example:
W/Firestore(29258):
W/Firestore(29258): // Old:
W/Firestore(29258): java.util.Date date = snapshot.getDate("created_at");
W/Firestore(29258): // New:
W/Firestore(29258): Timestamp timestamp = snapshot.getTimestamp("created_at");
W/Firestore(29258): java.util.Date date = timestamp.toDate();
W/Firestore(29258):
W/Firestore(29258): Please audit all existing usages of java.util.Date when you enable the new behavior. In a future release, the behavior will be changed to the new behavior, so if you do not follow these steps, YOUR APP MAY BREAK.
D/ApplicationLoaders(29258): ignored Vulkan layer search path /data/app/com.google.android.gms-1/lib/arm64:/data/app/com.google.android.gms-1/base.apk!/lib/arm64-v8a for namespace 0x7f77aab160
V/NativeCrypto(29258): Registering com/google/android/gms/org/conscrypt/NativeCrypto's 287 native methods...
D/NetworkSecurityConfig(29258): No Network Security Config specified, using platform default
I/ProviderInstaller(29258): Installed default security provider GmsCore_OpenSSL
W/art (29258): Before Android 4.1, method double java.util.concurrent.ThreadLocalRandom.internalNextDouble(double, double) would have incorrectly overridden the package-private method in java.util.Random
W/art (29258): Before Android 4.1, method int java.util.concurrent.ThreadLocalRandom.internalNextInt(int, int) would have incorrectly overridden the package-private method in java.util.Random
W/art (29258): Before Android 4.1, method long java.util.concurrent.ThreadLocalRandom.internalNextLong(long, long) would have incorrectly overridden the package-private method in java.util.Random
W/ManagedChannelImpl(29258): [{0}] Failed to resolve name. status={1}
W/Firestore(29258): (0.6.6-dev) [OnlineStateTracker]: Could not reach Cloud Firestore backend. Connection failed 1 times. Most recent error: Status{code=UNAVAILABLE, description=Unable to resolve host firestore.googleapis.com, cause=java.net.UnknownHostException: Unable to resolve host "firestore.googleapis.com": No address associated with hostname
W/Firestore(29258): at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:125)
W/Firestore(29258): at java.net.Inet6AddressImpl.lookupAllHostAddr(Inet6AddressImpl.java:74)
W/Firestore(29258): at java.net.InetAddress.getAllByName(InetAddress.java:752)
W/Firestore(29258): at io.grpc.internal.DnsNameResolver$JdkResolver.resolve(DnsNameResolver.java:497)
W/Firestore(29258): at io.grpc.internal.DnsNameResolver$1.run(DnsNameResolver.java:200)
W/Firestore(29258): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
W/Firestore(29258): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
W/Firestore(29258): at java.lang.Thread.run(Thread.java:760)
W/Firestore(29258): Caused by: android.system.GaiException: android_getaddrinfo failed: EAI_NODATA (No address associated with hostname)
W/Firestore(29258): at libcore.io.Posix.android_getaddrinfo(Native Method)
W/Firestore(29258): at libcore.io.ForwardingOs.android_getaddrinfo(ForwardingOs.java:55)
W/Firestore(29258): at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:106)
W/Firestore(29258): ... 7 more
W/Firestore(29258): }
W/Firestore(29258): This typically indicates that your device does not have a healthy Internet connection at the moment. The client will operate in offline mode until it is able to successfully connect to the backend.
W/ManagedChannelImpl(29258): [{0}] Failed to resolve name. status={1}
W/ManagedChannelImpl(29258): [{0}] Failed to resolve name. status={1}
W/ManagedChannelImpl(29258): [{0}] Failed to resolve name. status={1}
W/ManagedChannelImpl(29258): [{0}] Failed to resolve name. status={1}
W/ManagedChannelImpl(29258): [{0}] Failed to resolve name. status={1}
W/ManagedChannelImpl(29258): [{0}] Failed to resolve name. status={1}

```