func (r *recorder) ExportSpans(_ context.Context, s []trace.ReadOnlySpan) error {
	r.spans = append(r.spans, s...)
	return nil
}
ExportSpans records spans into the internal buffer
package tracetesting
import (
	"context"
	"go.opentelemetry.io/otel/sdk/trace"
)
var _ trace.SpanExporter = &recorder{}
type recorder struct {
	spans []trace.ReadOnlySpan
}