"""

    def __init__(
        self,
        scopes: Annotated[
            Optional[List[str]],
            Doc(
                """
                This will be filled by FastAPI.
                """
            ),
        ] = None,
    ):
        self.scopes: Annotated[
            List[str],
            Doc(
                """

	ResumeItemsSkipped uint64 `json:"-"`
	ResumeBytesDone    uint64 `json:"-"`
	ResumeBytesFailed  uint64 `json:"-"`
	ResumeBytesSkipped uint64 `json:"-"`

	// Filled on startup/restarts.
	QueuedBuckets []string

	// Filled during heal.
	HealedBuckets []string

	// ID of the current healing operation
	HealID string

	ItemsSkipped uint64
	BytesSkipped uint64

	RetryAttempts uint64

      const std::vector<int64_t>& unneeded_gradients,
      gtl::ArraySlice<AbstractTensorHandle*> output_gradients,
      absl::Span<AbstractTensorHandle*> result) const override;

  // Builds a tensor filled with ones with the same shape and dtype as `t`.
  absl::Status BuildOnesLike(const TapeTensor& t,
                             AbstractTensorHandle** result) const override;

  // Looks up the ID of a Gradient.

		b := NewWriterSize(tw, BufSize)
		b.WriteString("1234")
		tw.check(t, "", "")
		b.WriteString("56789012")   // longer than BufSize
		tw.check(t, "12345678", "") // but not enough (after filling the partially-filled buffer)
		b.Flush()
		tw.check(t, "123456789012", "")
	}
	{
		tw := &teststringwriter{}
		b := NewWriterSize(tw, BufSize)
		b.WriteString("123456789")   // long string, empty buffer:

			if err == nil {
				actualSize = int64(decSize)
			}
		default:
			actualSize = n
		}
	}
	if fi.Checksum == nil {
		// Trailing headers checksums should now be filled.
		fi.Checksum = opts.WantChecksum.AppendTo(nil, nil)
		if opts.EncryptFn != nil {
			fi.Checksum = opts.EncryptFn("object-checksum", fi.Checksum)
		}
	}
	for i, w := range writers {
		if w == nil {