         return Progress(totalUnitCount: self.totalUnitCountForRemoving(entry))
     }
 
+    /// The number of the work units that have to be performed when
+    /// reading `entry` from the receiver.
+    ///
+    /// - Parameter entry: The entry that will be read.
+    /// - Returns: The number of the work units.
     public func totalUnitCountForReading(_ entry: Entry) -> Int64 {
         switch entry.type {
         case .file, .symlink:

        return Progress(totalUnitCount: self.totalUnitCountForReading(entry))
    }

    public func totalUnitCountForAddingItem(at url: URL) -> Int64 {
        var count = Int64(0)
        do {

}

extension Archive {
    /// The number of the work units that have to be performed when
    /// removing `entry` from the receiver.
    ///
    /// - Parameter entry: The entry that will be removed.
    /// - Returns: The number of the work units.
    public func totalUnitCountForRemoving(_ entry: Entry) -> Int64 {
        return Int64(self.endOfCentralDirectoryRecord.offsetToStartOfCentralDirectory
                   - UInt32(entry.localSize))
