make wantlist updates to connected peers happen async, dramatically improves...

make wantlist updates to connected peers happen async, dramatically improves performance between connected nodes

bitswap.go

@@ -369,10 +369,12 @@ func (bs *bitswap) wantNewBlocks(ctx context.Context, bkeys []u.Key) {
 		message.AddEntry(k, kMaxPriority-i)
 	}
 	for _, p := range bs.engine.Peers() {
+		go func(p peer.ID) {
 			err := bs.send(ctx, p, message)
 			if err != nil {
 				log.Debugf("Error sending message: %s", err)
 			}
+		}(p)
 	}
 }