During some minimization efforts on the previous released version 28.2-jre, I noticed a spurious file in the published version on maven central:

```
tn@proteus:~/Downloads$ unzip -l guava-28.2-jre.jar  | grep swp
    16384  2019-09-18 17:29   com/google/common/collect/.ImmutableListMultimap.java.swp
```

Looks like an transient artefact from an editor that slipped into the release. It is not present in the android variant or in older releases (I checked at least 28.1-jre).

Minor things that can not be changed anymore but maybe a trigger for improvement of future releases.

Edit: I noticed that 29.0 has been released that does not contain this spurious file.
String unused = network.edgeConnectingOrNull(EndpointPair.unordered(N1, N2));
      fail("Expected IllegalArgumentException: " + ENDPOINTS_MISMATCH);
    } catch (IllegalArgumentException e) {
      assertThat(e).hasMessageThat().contains(ENDPOINTS_MISMATCH);
    }
  }
  @Override
  @Test
  public void incidentNodes_oneEdge() {
    addEdge(N1, N2, E12);
    assertThat(network.incidentNodes(E12).source()).isEqualTo(N1);
    assertThat(network.incidentNodes(E12).target()).isEqualTo(N2);
  }
  @Test
  public void edgesConnecting_oneEdge() {
    addEdge(N1, N2, E12);
    assertThat(network.edgesConnecting(N1, N2)).containsExactly(E12);
    
    
    assertThat(network.edgesConnecting(N2, N1)).isEmpty();
  }
  @Test
  public void inEdges_oneEdge() {
    addEdge(N1, N2, E12);
    assertThat(network.inEdges(N2)).containsExactly(E12);
    
    assertThat(network.inEdges(N1)).isEmpty();
  }
  @Test
  public void outEdges_oneEdge() {