* <ul>
     *   <li>Its execution does not cause any observable side effects.
     *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
     *       Objects.equal}{@code (k1, k2) &&} {@link Objects#equal}{@code (v1, v2)} implies that
     *       {@code Objects.equal(transformer.transform(k1, v1), transformer.transform(k2, v2))}.
     * </ul>
     *

     * <ul>
     *   <li>Its execution does not cause any observable side effects.
     *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
     *       Objects.equal}{@code (k1, k2) &&} {@link Objects#equal}{@code (v1, v2)} implies that
     *       {@code Objects.equal(transformer.transform(k1, v1), transformer.transform(k2, v2))}.
     * </ul>
     *

  /**
   * Puts the remaining bytes of a byte buffer into this sink. {@code bytes.position()} is the first
   * byte written, {@code bytes.limit() - 1} is the last. The position of the buffer will be equal
   * to the limit when this method returns.
   *
   * @param bytes a byte buffer
   * @return this instance
   * @since 23.0
   */
  @CanIgnoreReturnValue
  PrimitiveSink putBytes(ByteBuffer bytes);

   * contained references are {@linkplain Object#equals equal} to each other or both are absent.
   * Note that {@code Optional} instances of differing parameterized types can be equal.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> no differences.
   */
  @Override
  public abstract boolean equals(@CheckForNull Object object);

  /**
   * Returns a hash code for this instance.

    return delegate().elementSet();
  }

  @Override
  public Set<Entry<E>> entrySet() {
    return delegate().entrySet();
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    return object == this || delegate().equals(object);
  }

  @Override
  public int hashCode() {
    return delegate().hashCode();
  }

  @CanIgnoreReturnValue
  @Override

   See the License for the specific language governing permissions and
   limitations under the License.

===========================================================================
The common/types/pb/equal.go modification of proto.Equal logic
===========================================================================
Copyright (c) 2018 The Go Authors. All rights reserved.

Redistribution and use in source and binary forms, with or without

  val sectionIndexBuffer = Buffer()

  var previousMappedRanges: List<MappedRange>? = null

  for ((section, sectionMappedRanges) in sections) {
    // Skip sequential ranges when they are equal.
    if (sectionMappedRanges == previousMappedRanges) continue
    previousMappedRanges = sectionMappedRanges

    val sectionOffset = rangesBuffer.size.toInt() / 4

    // Section prefix.

    } catch (AssertionFailedError expected) {
      String expectedMessage =
          "the hash (1) of TestObject{group=1, item=1} [group 1, item 1] must be "
              + "equal to the hash (2) of TestObject{group=1, item=2} [group 1, item 2]";
      if (!expected.getMessage().contains(expectedMessage)) {
        fail("<" + expected.getMessage() + "> expected to contain <" + expectedMessage + ">");
      }

    } catch (AssertionFailedError expected) {
      String expectedMessage =
          "the hash (1) of TestObject{group=1, item=1} [group 1, item 1] must be "
              + "equal to the hash (2) of TestObject{group=1, item=2} [group 1, item 2]";
      if (!expected.getMessage().contains(expectedMessage)) {
        fail("<" + expected.getMessage() + "> expected to contain <" + expectedMessage + ">");
      }

            <!-- everything except { and } -->