PartNumber          int                 // only useful in case of GetObject/HeadObject
	CheckPrecondFn      CheckPreconditionFn // only set during GetObject/HeadObject/CopyObjectPart preconditional valuation
	EvalMetadataFn      EvalMetadataFn      // only set for retention settings, meant to be used only when updating metadata in-place.

	// Order parts metadata in accordance with distribution order.
	onlineDisks, partsMetadata = shuffleDisksAndPartsMetadataByIndex(onlineDisks, partsMetadata, fi)

	// Save current erasure metadata for validation.
	currentFI := fi

	// Allocate parts similar to incoming slice.
	fi.Parts = make([]ObjectPartInfo, len(parts))

	var checksum hash.Checksum
	checksum.Type = checksumType