return Region(m[k].To)
	}
	return 0
}

const (
	iso3166UserAssigned = 1 << iota
	ccTLD
	bcp47Region
)

func (r Region) typ() byte {
	return regionTypes[r]
}

// String returns the BCP 47 representation for the region.
// It returns "ZZ" for an unspecified region.
func (r Region) String() string {
	if r < isoRegionOffset {
		if r == 0 {
			return "ZZ"

// for 2-letter ISO codes. (The first isoRegionOffset regionIDs are reserved for
// the UN.M49 codes used for groups.)
const isoRegionOffset = 32

// regionTypes defines the status of a region for various standards.
// Size: 359 bytes, 359 elements
var regionTypes = [359]uint8{
	// Entry 0 - 3F
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

func StartRegion(ctx context.Context, regionType string) *Region {
	if !IsEnabled() {
		return noopRegion
	}
	id := fromContext(ctx).id
	userRegion(id, regionStartCode, regionType)
	return &Region{id, regionType}
}

// Region is a region of code whose execution time interval is traced.
type Region struct {
	id         uint64
	regionType string
}

var noopRegion = &Region{}

func getSigningKey(secretKey string, t time.Time, region string, stype serviceType) []byte {
	date := sumHMAC([]byte("AWS4"+secretKey), []byte(t.Format(yyyymmdd)))
	regionBytes := sumHMAC(date, []byte(region))
	service := sumHMAC(regionBytes, []byte(stype))
	signingKey := sumHMAC(service, []byte("aws4_request"))
	return signingKey
}

// getSignature final signature in hexadecimal form.

  for (int i = 1; i < kNumRegionTypeLists; ++i)
    if (failed(VerifyTypeRangesAreCompatible(op, input_type, region_types[i])))
      return failure();

  for (int i = 0; i < kNumRegionTypeLists; ++i)
    if (failed(VerifyTypeRangesAreCompatible(op, result_type, region_types[i])))
      return failure();

  for (int i = 0; i < kNumRegionTypeLists; ++i)

	Type string
}

// Region provides details about a Region event.
type Region struct {
	// Task is the ID of the task this region is associated with.
	Task TaskID

	// Type is the regionType that was passed to runtime/trace.StartRegion or runtime/trace.WithRegion.
	Type string
}

// Log provides details about a Log event.
type Log struct {
	// Task is the ID of the task this region is associated with.