MultipeerConnectivity Memory Leak in receive method

Question

I'm using MultipeerConnectivity Framework. The application intends to send and receive large audio files constantly.

In the receiver, the memory is allocated indefinitely.

When I write this method,

func session(_ session: MCSession, didReceive data: Data, fromPeer peerID: MCPeerID){
     let usingData:NSData = autoreleasepool{
            return  NSData(data: data)
        }
}

Why does autoreleasepool not seem to be effective and the memory not free?