ESServerSyncClearAllOperationsAction ESServerSyncAssignOperationAction backspace skip ESServerSyncAssignOperationAction option backspace always-skip ESServerSyncAssignOperationAction option arrow-right copy-a-to-b ESServerSyncAssignOperationAction option arrow-left copy-b-to-a ESServerSyncAssignOperationAction remove-a ESServerSyncAssignOperationAction remove-b