Function get_files 

pub fn get_files(
    selection: GetSelection,
    paths: &DvsPaths,
    backend: &Backend,
    options: GetOptions,
    ctx: &OperationContext,
) -> GetReport

Gets the selected files from storage, following options.on_conflict.

Never errors: every problem is reported in the returned rows or as the report’s problem.

Reports to ctx’s observer as it goes: hashing (only when the plan hashes some working file), planned once the plan and storage checks are done, then every row through file_finished exactly once, as soon as it is final (rows decided before the transfers first, then each transfer as it completes). A cancel stops files from starting: a file already downloading finishes (verified temp file + rename), the rest are cancelled.