android/guava/src/com/google/common/graph/NetworkBuilder.java
public <N1 extends N, E1 extends E> ImmutableNetwork.Builder<N1, E1> immutable() {
    NetworkBuilder<N1, E1> castBuilder = cast();
    return new ImmutableNetwork.Builder<>(castBuilder);
  }
public <N1 extends N, E1 extends E> ImmutableNetwork.Builder<N1, E1> immutable() {
    NetworkBuilder<N1, E1> castBuilder = cast();
    return new ImmutableNetwork.Builder<>(castBuilder);
  }
Returns an {@link ImmutableNetwork#Builder} with the properties of this {@link NetworkBuilder}.

<p>The returned builder can be used for populating an {@link ImmutableNetwork}.

@since NEXT