bitswap: fix a minor data race

race detector picked up a minor race condition, Since loop iteration
reuses the same local variable, its not safe to take its address and use
it concurrently. The fix is to rebind the variable into a controlled
scope (creating a new variable) and taking the address of that to pass
outwards.

License: MIT
Signed-off-by: Jeromy <why@ipfs.io>

exchange/bitswap/workers.go

@@ -173,6 +173,7 @@ func (bs *Bitswap) rebroadcastWorker(parent context.Context) {
 		case <-broadcastSignal.C: // resend unfulfilled wantlist keys
 			log.Event(ctx, "Bitswap.Rebroadcast.active")
 			for _, e := range bs.wm.wl.Entries() {
+				e := e
 				bs.findKeys <- &e
 			}
 		case <-parent.Done():