synchronized Optional<DiscoveryPeer> getAndTouch(final Bytes id) {
    for (int i = 0; i <= tailIndex; i++) {
      final DiscoveryPeer p = kBucket[i];
      if (id.equals(p.getId())) {
        arraycopy(kBucket, 0, kBucket, 1, i);
        kBucket[0] = p;
        return Optional.of(p);
      }
    }
    return Optional.empty();
  }
Returns the peer with the provided ID if it exists in the bucket.

<p>This operation presupposes that the system has been in recent contact with this peer, hence
it relocates it to the head of the list.

@param id The peer's ID (public key).
@return An empty optional if the peer was not a member of this bucket, or a filled optional if
    it was.
ethereum/p2p/src/main/java/org/hyperledger/besu/ethereum/p2p/discovery/internal/Bucket.java