defer cancel()

	l, err := lc.Listen(ctx, "tcp", net.JoinHostPort(host, port))
	if err != nil {
		return err
	}

	// As we are able to listen on this network, the port is not in use.
	// Close the listener and continue check other networks.
	return l.Close()

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	defer cancel()

	l, err := lc.Listen(ctx, "tcp", net.JoinHostPort(host, port))
	if err != nil {
		return err
	}

	// As we are able to listen on this network, the port is not in use.
	// Close the listener and continue check other networks.
	return l.Close()

  Set<N> successors();

  Set<E> incidentEdges();

  Set<E> inEdges();

  Set<E> outEdges();

  /**
   * Returns the set of edges connecting the origin node to {@code node}. For networks without
   * parallel edges, this set cannot be of size greater than one.
   */
  Set<E> edgesConnecting(N node);

  /**
   * Returns the node that is adjacent to the origin node along {@code edge}.
   *

Content-Length: 1759
Connection: keep-alive
```

The network requests also contain more data, such as the `Accept-Encoding: gzip` header added by OkHttp to advertise support for response compression. The network interceptor's `Chain` has a non-null `Connection` that can be used to interrogate the IP address and TLS configuration that were used to connect to the webserver.

### Choosing between application and network interceptors

  final MapIteratorCache<N, NetworkConnections<N, E>> nodeConnections;

  // We could make this a Map<E, EndpointPair<N>>. It would make incidentNodes(edge) slightly
  // faster, but also make Networks consume 5 to 20+% (increasing with average degree) more memory.
  final MapIteratorCache<E, N> edgeToReferenceNode; // referenceNode == source if directed

  final MapIteratorCache<N, NetworkConnections<N, E>> nodeConnections;

  // We could make this a Map<E, EndpointPair<N>>. It would make incidentNodes(edge) slightly
  // faster, but also make Networks consume 5 to 20+% (increasing with average degree) more memory.
  final MapIteratorCache<E, N> edgeToReferenceNode; // referenceNode == source if directed

	case strings.Contains(err.Error(), "server closed idle connection"):
		return true
	}

	return false
}

// Converts network error to storageErr. This function is
// written so that the storageAPI errors are consistent
// across network disks.
func toStorageErr(err error) error {
	if err == nil {
		return nil
	}

	if isNetworkError(err) {
		return errDiskNotFound
	}

  public void validateUndirectedEdges() {
    for (Integer node : network.nodes()) {
      new EqualsTester()
          .addEqualityGroup(
              network.inEdges(node), network.outEdges(node), network.incidentEdges(node))
          .testEquals();
      new EqualsTester()
          .addEqualityGroup(
              network.predecessors(node), network.successors(node), network.adjacentNodes(node))
          .testEquals();

        assertThat(network.incidentEdges(node).size() + selfLoopCount)
            .isEqualTo(network.inDegree(node) + network.outDegree(node));
        assertThat(network.inEdges(node)).hasSize(network.inDegree(node));
        assertThat(network.outEdges(node)).hasSize(network.outDegree(node));
      } else {
        assertThat(network.predecessors(node)).isEqualTo(network.adjacentNodes(node));