assertEquals(pair.forward, copy.forward);
    assertEquals(pair.backward, copy.backward);
    assertSame(copy.backward, copy.forward.inverse());
    assertSame(copy.forward, copy.backward.inverse());
  }

  private static class BiMapPair<K, V> implements Serializable {
    final BiMap<K, V> forward;
    final BiMap<V, K> backward;

    BiMapPair(BiMap<K, V> original) {
      this.forward = original;

    assertEquals(pair.forward, copy.forward);
    assertEquals(pair.backward, copy.backward);
    assertSame(copy.backward, copy.forward.inverse());
    assertSame(copy.forward, copy.backward.inverse());
  }

  private static class BiMapPair<K, V> implements Serializable {
    final BiMap<K, V> forward;
    final BiMap<V, K> backward;

    BiMapPair(BiMap<K, V> original) {
      this.forward = original;

   */
  void setDelegates(Map<K, V> forward, Map<V, K> backward) {
    checkState(delegate == null);
    checkState(inverse == null);
    checkArgument(forward.isEmpty());
    checkArgument(backward.isEmpty());
    checkArgument(forward != backward);
    delegate = forward;
    inverse = makeInverse(backward);
  }

  AbstractBiMap<V, K> makeInverse(Map<V, K> backward) {
    return new Inverse<>(backward, this);
  }

- [All](/pkg/slices#All) returns an iterator over slice indexes and values.
- [Values](/pkg/slices#Values) returns an iterator over slice elements.
- [Backward](/pkg/slices#Backward) returns an iterator that loops over
  a slice backward.
- [Collect](/pkg/slices#Collect) collects values from an iterator into
  a new slice.
- [AppendSeq](/pkg/slices#AppendSeq) appends values from an iterator to
  an existing slice.

   */
  void setDelegates(Map<K, V> forward, Map<V, K> backward) {
    checkState(delegate == null);
    checkState(inverse == null);
    checkArgument(forward.isEmpty());
    checkArgument(backward.isEmpty());
    checkArgument(forward != backward);
    delegate = forward;
    inverse = makeInverse(backward);
  }

  AbstractBiMap<V, K> makeInverse(Map<V, K> backward) {
    return new Inverse<>(backward, this);
  }

    // backward_ops
    %res_b1 = "tf.Identity"(%res_t) {_embedding_pipelining = "backward", _replication_info = "repl_info"} : (tensor<i32>) -> tensor<i32>
    %res_b2 = "tf.Identity"(%res_t) {_embedding_pipelining = "backward", _replication_info = "repl_info"} : (tensor<i32>) -> tensor<i32>
    %res_b3 = "tf.Identity"(%res_t) {_embedding_pipelining = "backward", _replication_info = "repl_info"} : (tensor<i32>) -> tensor<i32>

	// length.  This catches the cases where src and dest are in different types
	// of storage such as stack and static to avoid doing backward move when not
	// necessary.

	SUB	SRC, TGT, TMP	// dest - src
	CMPU	TMP, LEN, CR2	// < len?
	BC	12, 8, backward // BLT CR2 backward

	// Copying forward if no overlap.

	BC	12, 6, checkbytes	// BEQ CR1, checkbytes
	SRDCC	$3, DWORDS, OCTWORDS	// 64 byte chunks?

For etcd 3.1+, the
[go-grpc-prometheus](https://github.com/grpc-ecosystem/go-grpc-prometheus)
metrics format, which backward incompatibly replaces the 3.0 legacy grpc metric
format, is exposed in both the 3.1 format and in the 3.0. This preserves
backward compatibility.

For etcd 3.1+, the `--metrics=extensive` must be set on etcd for grpc request

        .containsExactly(Country.CANADA, Country.SWITZERLAND, Country.CHILE)
        .inOrder();
    // backward map ordered by country
    assertThat(bimap.inverse().keySet())
        .containsExactly(Country.CANADA, Country.CHILE, Country.SWITZERLAND)
        .inOrder();
    // backward map ordered by country (even for currency values)
    assertThat(bimap.inverse().values())

	"deprecatedSource":         "deprecatedSource is the deprecated field assuring backward compatibility with core.v1 Event type.",
	"deprecatedFirstTimestamp": "deprecatedFirstTimestamp is the deprecated field assuring backward compatibility with core.v1 Event type.",
	"deprecatedLastTimestamp":  "deprecatedLastTimestamp is the deprecated field assuring backward compatibility with core.v1 Event type.",