DataSenderReceiver

Tsvrc.DataTransfer.DataSenderReceiver sits on top of DataChunkReceiver and is purely an ergonomics layer: it turns the receiver's raw hooks (OnTransferStarted, OnChunksAssembled, OnChunkStored, ...) into a clean, receiver-focused public API: LastData, LastChunkIndex, LastTotalChunks, and four events (OnDataReceptionStartedEvent, ...StoppedEvent, ...CompletedEvent, OnDataChunkReceivedEvent) with matching protected virtual hooks a subclass overrides without ever touching the raw chunk arrays underneath. OnDataReceptionStartedEvent and ...StoppedEvent don't update any Last* property; LastChunkIndex/LastTotalChunks are set before OnDataChunkReceivedEvent fires, and LastData is set before OnDataReceptionCompletedEvent fires, so both are always safe to read from inside their matching subscriber.

The same deferred-emission pattern, one layer up

Just as DataSender defers its stop/complete broadcasts by a frame, DataSenderReceiver defers its own OnDataReceptionStopped/Completed emission the same way and for the same reason: at the point these fire, ExecuteStop/ExecuteComplete is still on the call stack, so a subscriber that reacts by immediately starting a new transfer would corrupt the new transfer's state if the emission happened synchronously. The assembled data itself is staged in a private field (_pendingCompletionData) rather than written straight to LastData, specifically so a new transfer starting inside that one-frame gap, which resets receiver state, can't clobber it before the deferred emit reads it. LastData is only ever assigned atomically with the deferred completion event actually firing.

Both pending flags (_pendingCompletion, _pendingStop) are cleared by ResetReceiverState, which runs when a new transfer starts. That's what suppresses a stale emission for a transfer that's already been superseded: the deferred call still fires, finds its flag already cleared, and returns without emitting anything.

What this layer adds vs. what it doesn't

There's no new validation here; every correctness guarantee (sender verification, duplicate suppression, chunk-count bounds) lives one layer down in DataChunkReceiver and isn't repeated here.

Usage

Most consumers use DataTransferer directly and never touch this layer. Subclass DataSenderReceiver itself only if you want the sender/receiver plumbing without DataTransferer's transfer-specific event names. Override OnDataReceptionCompleted and read LastData:

protected override void OnDataReceptionCompleted()
{
    string received = LastData;
    // ...
}