RLMClientResetMode

Data written to the Realm after the local copy of the Realm diverged from the backup remote copy will be present in the local recovery copy of the Realm file. The re-downloaded Realm will initially contain only the data present at the time the Realm was backed up on the server.

@see: ``rlmSync_clientResetBackedUpRealmPath`` and ``RLMSyncErrorActionToken`` for more information on accessing the recovery directory and error information.

The manual client reset mode handler can be set in two places:
 1. As an ErrorReportingBlock argument at ``RLMSyncConfiguration.manualClientResetHandler``.
 2. As an ErrorReportingBlock in the ``RLMSyncManager.errorHandler`` property.
 @see: ``RLMSyncManager.errorHandler``

 When an ``RLMSyncErrorClientResetError`` is thrown, the following rules determine which block is executed:
 - If an error reporting block is set in ``.manualClientResetHandler`` and the ``RLMSyncManager.errorHandler``, the ``.manualClientResetHandler`` block will be executed.
 - If an error reporting block is set in either the ``.manualClientResetHandler`` or the ``RLMSyncManager``, but not both, the single block will execute.
 - If no block is set in either location, the client reset will not be handled. The application will likely need to be restarted and unsynced local changes may be lost.
@note: The ``RLMSyncManager.errorHandler`` is still invoked under all ``RLMSyncError``s *other than* ``RLMSyncErrorClientResetError``.
- see: ``RLMSyncError`` for an exhaustive list.

All unsynchronized local changes are automatically discarded and the local state is automatically reverted to the most recent state from the server. Unsynchronized changes can then be recovered in the post-client-reset callback block.

If ``RLMClientResetModeDiscardLocal`` is enabled but the client reset operation is unable to complete
then the client reset process reverts to manual mode. Example) During a destructive schema change this
mode will fail and invoke the manual client reset handler.

The RLMClientResetModeDiscardLocal mode supports two client reset callbacks -- ``RLMClientResetBeforeBlock``, ``RLMClientResetAfterBlock`` -- which can be passed as arguments when creating the ``RLMSyncConfiguration``.
@see: ``RLMClientResetAfterBlock`` and ``RLMClientResetBeforeBlock``

All unsynchronized local changes are automatically discarded and the local state is automatically reverted to the most recent state from the server. Unsynchronized changes can then be recovered in the post-client-reset callback block.

If ``RLMClientResetModeDiscardUnsyncedChanges`` is enabled but the client reset operation is unable to complete
then the client reset process reverts to manual mode. Example) During a destructive schema change this
mode will fail and invoke the manual client reset handler.

The RLMClientResetModeDiscardUnsyncedChanges mode supports two client reset callbacks -- ``RLMClientResetBeforeBlock``, ``RLMClientResetAfterBlock`` -- which can be passed as arguments when creating the ``RLMSyncConfiguration``.
@see: ``RLMClientResetAfterBlock`` and ``RLMClientResetBeforeBlock``

The client device will download a realm realm which reflects the latest state of the server after a client reset. A recovery process is run locally in an attempt to integrate the server version with any local changes from before the client reset occurred.

The changes are integrated with the following rules:
1. Objects created locally that were not synced before client reset will be integrated.
2. If an object has been deleted on the server, but was modified on the client, the delete takes precedence and the update is discarded
3. If an object was deleted on the client, but not the server, then the client delete instruction is applied.
4. In the case of conflicting updates to the same field, the client update is applied.

If the recovery integration fails, the client reset process falls back to ``RLMClientResetModeManual``.
The recovery integration will fail if the "Client Recovery" setting is not enabled on the server.
Integration may also fail in the event of an incompatible schema change.

The RLMClientResetModeRecoverUnsyncedChanges mode supports two client reset callbacks -- ``RLMClientResetBeforeBlock``, ``RLMClientResetAfterBlock`` -- which can be passed as arguments when creating the ``RLMSyncConfiguration``.
@see: ``RLMClientResetAfterBlock`` and ``RLMClientResetBeforeBlock``

The client device will download a realm with objects reflecting the latest version of the server. A recovery process is run locally in an attempt to integrate the server version with any local changes from before the client reset occurred.

The changes are integrated with the following rules:
1. Objects created locally that were not synced before client reset will be integrated.
2. If an object has been deleted on the server, but was modified on the client, the delete takes precedence and the update is discarded
3. If an object was deleted on the client, but not the server, then the client delete instruction is applied.
4. In the case of conflicting updates to the same field, the client update is applied.

If the recovery integration fails, the client reset process falls back to ``RLMClientResetModeDiscardUnsyncedChanges``.
The recovery integration will fail if the "Client Recovery" setting is not enabled on the server.
Integration may also fail in the event of an incompatible schema change.

The RLMClientResetModeRecoverOrDiscardUnsyncedChanges mode supports two client reset callbacks -- ``RLMClientResetBeforeBlock``, ``RLMClientResetAfterBlock`` -- which can be passed as arguments when creating the ``RLMSyncConfiguration``.
@see: ``RLMClientResetAfterBlock`` and ``RLMClientResetBeforeBlock``