Method begin

switch/source/progress.cpp:36–41

UiProgressSink runs on the TransferJob worker thread: every call only mirrors figures into TransferStatus. It does not render — the main loop draws the transfer modal from TransferStatus::snapshot() every frame, so the UI keeps animating while the copy runs on the worker. The batch active flag is owned by TransferStatus::beginLocalBatch / end, raised and lowered by the TransferJob around the whole

// TransferStatus::beginLocalBatch / end, raised and lowered by the TransferJob
// around the whole batch.
void UiProgressSink::begin(const std::string& mode, size_t totalFiles)
{
    // A backup sink carries a cancel flag; a restore sink does not. That is
    // exactly the "may this run be cancelled?" fact the modal needs.
    TransferStatus::beginLocalRun(mode, totalFiles, mCancelFlag != nullptr);
}

void UiProgressSink::startFile(const std::string& name, u64 size)
{