tracer: add IsRecording to span interface

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

tracer/memory/memory.go

@@ -89,6 +89,10 @@ func (s *Span) Tracer() tracer.Tracer {
 	return s.tracer
 }
 
+func (s *Span) IsRecording() bool {
+	return true
+}
+
 type Event struct {
 	name   string
 	labels []interface{}

tracer/noop.go

@@ -120,6 +120,10 @@ func (s *noopSpan) SetStatus(st SpanStatus, msg string) {
 	s.statusMsg = msg
 }
 
+func (s *noopSpan) IsRecording() bool {
+	return false
+}
+
 // NewTracer returns new memory tracer
 func NewTracer(opts ...Option) Tracer {
 	return &noopTracer{

tracer/tracer.go

@@ -78,4 +78,6 @@ type Span interface {
 	TraceID() string
 	// SpanID returns span id
 	SpanID() string
+	// IsRecording returns the recording state of the Span.
+	IsRecording() bool
 }