// The s3ChunkedReader returns io.EOF when the final 0-length chunk is read.
func newUnsignedV4ChunkedReader(req *http.Request, trailer bool) (io.ReadCloser, APIErrorCode) {
	if trailer {
		// Discard anything unsigned.
		req.Trailer = make(http.Header)
		trailers := req.Header.Values(awsTrailerHeader)
		for _, key := range trailers {
			req.Trailer.Add(key, "")
		}
	} else {
		req.Trailer = nil
	}

const (
	// Lock maintenance interval.
	lockMaintenanceInterval = 1 * time.Minute

	// Lock validity duration
	lockValidityDuration = 1 * time.Minute
)

// lockMaintenance loops over all locks and discards locks
// that have not been refreshed for some time.
func lockMaintenance(ctx context.Context) {
	if !globalIsDistErasure {
		return
	}

	// Initialize a new ticker with 1 minute between each ticks.