type EvalRetentionBypassFn func(o ObjectInfo, gerr error) error

// GetObjectInfoFn is the signature of GetObjectInfo function.
type GetObjectInfoFn func(ctx context.Context, bucket, object string, opts ObjectOptions) (ObjectInfo, error)

// WalkVersionsSortOrder represents the sort order in which versions of an
// object should be returned by ObjectLayer.Walk method
type WalkVersionsSortOrder uint8

const (

	}

	// Initialize erasure metadata.
	for index := range partsMetadata {
		partsMetadata[index] = fi
	}

	// Guess content-type from the extension if possible.
	if userDefined["content-type"] == "" {
		userDefined["content-type"] = mimedb.TypeByExtension(path.Ext(object))
	}

	// if storageClass is standard no need to save it as part of metadata.

				// the CopyObject API does not require that the caller send us this final checksum, we need
				// to compute it server-side, with the same type as the source object.
				if dstOpts.WantChecksum != nil && dstOpts.WantChecksum.Type.IsMultipartComposite() {
					dstOpts.WantServerSideChecksumType = dstOpts.WantChecksum.Type.Base()
					srcInfo.Reader.AddServerSideChecksumHasher(dstOpts.WantServerSideChecksumType)
					dstOpts.WantChecksum = nil
				}

		return
	} else if checksumType.IsSet() && !checksumType.Is(hash.ChecksumTrailing) {
		opts.WantChecksum = &hash.Checksum{Type: checksumType}
	}

	if opts.WantChecksum != nil {
		opts.WantChecksum.Type |= hash.ChecksumMultipart | hash.ChecksumIncludesMultipart
	}

	newMultipartUpload := objectAPI.NewMultipartUpload

	res, err := newMultipartUpload(ctx, bucket, object, opts)

			// and SSE-S3 is specified do not preserve
			// the incoming etag.
			userDefined["etag"] = opts.PreserveETag
		}
	}

	// Guess content-type from the extension if possible.
	if userDefined["content-type"] == "" {
		userDefined["content-type"] = mimedb.TypeByExtension(path.Ext(object))
	}

	// if storageClass is standard no need to save it as part of metadata.