Fix stalls for responsive transfer tests

Looks like there's a timing issue between marking things complete, and already having decided to read the data from incomplete chunks.

reader.go

@@ -224,8 +224,11 @@ func (r *reader) readOnceAt(b []byte, pos int64, ctxErr *error) (n int, err erro
 		r.log(log.Fstr("error reading torrent %s piece %d offset %d, %d bytes: %v",
 			r.t.infoHash.HexString(), firstPieceIndex, firstPieceOffset, len(b1), err))
 		if !r.t.updatePieceCompletion(firstPieceIndex) {
-			r.log(log.Fstr("piece %d completion unchanged", firstPieceIndex))
+			r.log(log.Fstr("piece %d completion unchanged (%+v)", firstPieceIndex, r.t.piece(firstPieceIndex).completion()))
 		}
+		r.t.iterPeers(func(c *Peer) {
+			c.updateRequests()
+		})
 		// Update the rest of the piece completions in the readahead window, without alerting to
 		// changes (since only the first piece, the one above, could have generated the read error
 		// we're currently handling).

torrent.go

@@ -1760,13 +1760,14 @@ func (t *Torrent) pieceHashed(piece pieceIndex, passed bool, hashIoErr error) {
 			c._stats.incrementPiecesDirtiedGood()
 		}
 		t.clearPieceTouchers(piece)
+		p.incrementPendingWrites()
 		t.cl.unlock()
 		err := p.Storage().MarkComplete()
 		if err != nil {
 			t.logger.Printf("%T: error marking piece complete %d: %s", t.storage, piece, err)
 		}
 		t.cl.lock()
-
+		p.decrementPendingWrites()
 		if t.closed.IsSet() {
 			return
 		}