// (indicating that the batch contains only CPU samples) and adds each
// sample contained therein to the provided samples list.
func addCPUSamples(samples []cpuSample, b batch) ([]cpuSample, error) {
	if !b.isCPUSamplesBatch() {
		return nil, fmt.Errorf("internal error: addCPUSamples called on non-CPU-sample batch")
	}
	r := bytes.NewReader(b.data)

type extraStringID uint64

// stackID is an index into the stack table for a generation.
type stackID uint64

// cpuSample represents a CPU profiling sample captured by the trace.
type cpuSample struct {
	schedCtx
	time  Time
	stack stackID
}

// asEvent produces a complete Event from a cpuSample. It needs
// the evTable from the generation that created it.
//

type Reader struct {
	r           *bufio.Reader
	lastTs      Time
	gen         *generation
	spill       *spilledBatch
	spillErr    error // error from reading spill
	frontier    []*batchCursor
	cpuSamples  []cpuSample
	order       ordering
	emittedSync bool

	go121Events *oldTraceConverter
}

// NewReader creates a new trace reader.
func NewReader(r io.Reader) (*Reader, error) {
	br := bufio.NewReader(r)

	},
	EvString: event.Spec{
		Name:    "String",
		Args:    []string{"id"},
		HasData: true,
	},
	EvCPUSamples: event.Spec{
		Name: "CPUSamples",
	},
	EvCPUSample: event.Spec{
		Name: "CPUSample",
		Args: []string{"time", "m", "p", "g", "stack"},
		// N.B. There's clearly a timestamp here, but these Events
		// are special in that they don't appear in the regular
		// M streams.
	},

	EvUserRegion:        {"UserRegion", 11, true, []string{"taskid", "mode", "typeid"}, []string{"name"}},
	EvUserLog:           {"UserLog", 11, true, []string{"id", "keyid"}, []string{"category", "message"}},
	EvCPUSample:         {"CPUSample", 19, true, []string{"ts", "p", "g"}, nil},
}

//gcassert:inline
func (p *parser) allocateStack(size uint64) []uint64 {
	if size == 0 {
		return nil
	}