"github.com/pierrec/lz4/v4"
)

type countUpReader struct {
	reader    io.Reader
	bytesRead int64
}

// Max bzip2 concurrency across calls. 50% of GOMAXPROCS.
var bz2Limiter = pbzip2.CreateConcurrencyPool((runtime.GOMAXPROCS(0) + 1) / 2)

func (r *countUpReader) Read(p []byte) (n int, err error) {
	n, err = r.reader.Read(p)
	atomic.AddInt64(&r.bytesRead, int64(n))
	return n, err
}

	"github.com/klauspost/compress/zstd"
	gzip "github.com/klauspost/pgzip"
	"github.com/pierrec/lz4/v4"
)

// Max bzip2 concurrency across calls. 50% of GOMAXPROCS.
var bz2Limiter = pbzip2.CreateConcurrencyPool((runtime.GOMAXPROCS(0) + 1) / 2)

func detect(r *bufio.Reader) format {
	z, err := r.Peek(4)
	if err != nil {
		return formatUnknown
	}
	for _, f := range magicHeaders {