for len(fieldBuf) >= 4 { // need at least tag and size
				attrTag := fieldBuf.uint16()
				attrSize := int(fieldBuf.uint16())
				if len(fieldBuf) < attrSize {
					continue parseExtras
				}
				attrBuf := fieldBuf.sub(attrSize)
				if attrTag != 1 || attrSize != 24 {
					continue // Ignore irrelevant attributes
				}

				const ticksPerSecond = 1e7    // Windows timestamp resolution

	size := 0
	// Figure out the data block length.
	for _, block := range enBlocks[:dataBlocks] {
		size += len(block)
	}
	return size
}

// Writes all the data blocks from encoded blocks until requested
// outSize length. Provides a way to skip bytes until the offset.
func writeDataBlocks(ctx context.Context, dst io.Writer, enBlocks [][]byte, dataBlocks int, offset int64, length int64) (int64, error) {
	// Offset and out size cannot be negative.