* Otherwise, at least reduce <i>explicit</i> dependencies on this type by using lambda expressions
 * or method references instead of classes, leaving your code easier to migrate in the future.
 *
 * <p>To use an existing function (say, named {@code function}) in a context where the <i>other
 * type</i> of function is expected, use the method reference {@code function::apply}. A future

   *
   * <p><b>Warning:</b> This method, which reencodes the input before processing it, is useful only
   * for cross-language compatibility. For other use cases, prefer {@link #putUnencodedChars}, which
   * is faster, produces the same output across Java releases, and processes every {@code char} in
   * the input, even if some are invalid.
   */
  @CanIgnoreReturnValue

 * iterators that don't support {@code remove()}. Otherwise, all optional operations are supported.
 * Null row keys, columns keys, and values are not supported.
 *
 * <p>Lookups by row key are often faster than lookups by column key, because the data is stored in
 * a {@code Map<R, Map<C, V>>}. A method call like {@code column(columnKey).get(rowKey)} still runs

  private final ElementOrder<E> edgeOrder;

  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

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * This class provides a skeletal implementation of the {@code Iterator} interface, to make this
 * interface easier to implement for certain types of data sources.
 *
 * <p>{@code Iterator} requires its implementations to support querying the end-of-data status