"io"
	"math"
)

// MonitoredReader represents a throttled reader subject to bandwidth monitoring
type MonitoredReader struct {
	r        io.Reader
	throttle *bucketThrottle
	ctx      context.Context // request context
	lastErr  error           // last error reported, if this non-nil all reads will fail.
	m        *Monitor
	opts     *MonitorReaderOptions
}

// https://docs.aws.amazon.com/AmazonS3/latest/userguide/checking-object-integrity.html
// Returns ErrInvalidChecksum if a problem with the checksum is found.
func (r *Reader) AddChecksum(req *http.Request, ignoreValue bool) error {
	cs, err := GetContentChecksum(req.Header)
	if err != nil {
		return ErrInvalidChecksum
	}
	if cs == nil {
		return nil
	}
	r.contentHash = *cs
	if cs.Type.Trailing() {