fix(bs/n) remove unnecessary variable

to remove ambiguity

(before it was possible to loop over either topics or keys

by only keeping keys, there's no confusing about what to use for the
loop range

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

exchange/bitswap/notifications/notifications.go

@@ -37,14 +37,14 @@ func (ps *impl) Shutdown() {
 // is closed if the |ctx| times out or is cancelled, or after sending len(keys)
 // blocks.
 func (ps *impl) Subscribe(ctx context.Context, keys ...u.Key) <-chan *blocks.Block {
-	topics := toStrings(keys)
+
 	blocksCh := make(chan *blocks.Block, len(keys))
 	valuesCh := make(chan interface{}, len(keys))
-	ps.wrapped.AddSub(valuesCh, topics...)
+	ps.wrapped.AddSub(valuesCh, toStrings(keys)...)
 
 	go func() {
 		defer func() {
-			ps.wrapped.Unsub(valuesCh, topics...)
+			ps.wrapped.Unsub(valuesCh, toStrings(keys)...)
 			close(blocksCh)
 		}()
 		for _, _ = range keys {