new

    /// Instantiates a new PMMR backend.
    /// Use the provided dir to store its files.

unpruned_size

    /// Number of elements in the PMMR stored by this backend. Only produces the
    /// fully sync'd size.

data_size

    /// Number of elements in the underlying stored data. Extremely dependent on
    /// pruning and compaction.

hash_size

    /// Size of the underlying hashed data. Extremely dependent on pruning
    /// and compaction.

sync

    /// Syncs all files to disk. A call to sync is required to ensure all the
    /// data has been successfully written to disk.

discard

/// Discard the current, non synced state of the backend.

data_file_path

/// Return the data file path

check_compact

    /// Takes the leaf_set at a given cutoff_pos and generates an updated
    /// prune_list. Saves the updated prune_list to disk
    /// Compacts the hash and data files based on the prune_list and saves both
    /// to disk.
    ///
    /// A cutoff position limits compaction on recent data.
    /// This will be the last position of a particular block
    /// to keep things aligned.
    /// The block_marker in the db/index for the particular block
    /// will have a suitable output_pos.
    /// This is used to enforce a horizon after which the local node
    /// should have all the data to allow rewinding.