pub type ClientModuleMigrationFn = for<'r, 'tx> fn(&'r mut DatabaseTransaction<'tx>, Vec<(Vec<u8>, OperationId)>, Vec<(Vec<u8>, OperationId)>) -> BoxFuture<'r, Result<Option<(Vec<(Vec<u8>, OperationId)>, Vec<(Vec<u8>, OperationId)>)>>>;Expand description
ClientMigrationFn is a function that modules can implement to “migrate”
the database to the next database version.