TapeVSpace vspace(ctx);
  std::vector<int64_t> target_tensor_ids = MakeTensorIDList(targets);
  std::vector<int64_t> source_tensor_ids = MakeTensorIDList(sources);
  tensorflow::gtl::FlatSet<int64_t> sources_set(source_tensor_ids.begin(),
                                                source_tensor_ids.end());
  std::unordered_map<int64_t, TapeTensor> sources_that_are_targets;
  for (int i = 0; i < target_tensor_ids.size(); ++i) {

		return
	}

	type Smallint int8

	type MigrateInt struct {
		Int8 Smallint
	}

	tracer := Tracer{
		Logger: DB.Config.Logger,
		Test: func(ctx context.Context, begin time.Time, fc func() (sql string, rowsAffected int64), err error) {
			sql, _ := fc()
			if strings.HasPrefix(sql, "ALTER TABLE \"migrate_ints\" ALTER COLUMN \"int8\" TYPE smallint") {

    const std::vector<std::string>& device_names = ListDeviceNames(ctx_0);
    ASSERT_TRUE(std::find(device_names.begin(), device_names.end(),
                          remote_device) != device_names.end());
  }

  {
    const std::vector<std::string>& device_names = ListDeviceNames(ctx_1);
    ASSERT_TRUE(std::find(device_names.begin(), device_names.end(),
                          remote_device) != device_names.end());
  }

 */
abstract class EventListener {
  /**
   * Invoked as soon as a call is enqueued or executed by a client. In case of thread or stream
   * limits, this call may be executed well before processing the request is able to begin.
   *
   * This will be invoked only once for a single [Call]. Retries of different routes or redirects
   * will be handled within the boundaries of a single [callStart] and [callEnd]/[callFailed] pair.
   */

    }
  }

  /**
   * Removes a number of occurrences of the specified element from this multiset. If the multiset
   * contains fewer than this number of occurrences to begin with, all occurrences will be removed.
   *
   * @param element the element whose occurrences should be removed
   * @param occurrences the number of occurrences of the element to remove

      return false;
    }

    /*
     * Note that we allow (in contravention of a strict interpretation of the relevant RFCs) domain
     * parts other than the last may begin with a digit (for example, "3com.com"). It's important to
     * disallow an initial digit in the last part; it's the only thing that stops an IPv4 numeric
     * address like 127.0.0.1 from looking like a valid domain name.

			expectedAuthField: signValues{},
			expectedErrCode:   ErrAuthHeaderEmpty,
		},
		// Test case - 2.
		// Test case with no sign v4 Algorithm prefix.
		// A valid authorization string should begin(prefix)
		{
			inputV4AuthStr:    "no-singv4AlgorithmPrefix",
			expectedAuthField: signValues{},
			expectedErrCode:   ErrSignatureVersionNotSupported,
		},
		// Test case - 3.

        // has now been moved after index.
        return new MoveDesc<>(actualLastElement, changes.replaced);
      }
    }
    // Trickled element was after index to begin with, no adjustment needed.
    return changes;
  }

  @CheckForNull
  private MoveDesc<E> fillHole(int index, E toTrickle) {
    Heap heap = heapForIndex(index);

            "42.42.42.ab",
            "3ffe::1.net",
            "3ffe::1::1",
            "1::2::3::4:5",
            "::7:6:5:4:3:2:", // should end with ":0"
            ":6:5:4:3:2:1::", // should begin with "0:"
            "2001::db:::1",
            "FEDC:9878",
            "+1.+2.+3.4",
            "1.2.3.4e0",
            "6:5:4:3:2:1:0", // too few parts
            "::7:6:5:4:3:2:1:0", // too many parts

  @Override
  boolean add(@ParametricNullness E element);

  /**
   * Removes a number of occurrences of the specified element from this multiset. If the multiset
   * contains fewer than this number of occurrences to begin with, all occurrences will be removed.
   * Note that if {@code occurrences == 1}, this is functionally equivalent to the call {@code
   * remove(element)}.
   *