v3 (#404)

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Reviewed-on: #404
Co-authored-by: Evstigneev Denis <danteevstigneev@yandex.ru>
Co-committed-by: Evstigneev Denis <danteevstigneev@yandex.ru>

tracer/noop.go

@@ -18,6 +18,10 @@ func (t *noopTracer) Spans() []Span {
 	return t.spans
 }
 
+func (t *noopTracer) Enabled() bool {
+	return t.opts.Enabled
+}
+
 func (t *noopTracer) Start(ctx context.Context, name string, opts ...SpanOption) (context.Context, Span) {
 	options := NewSpanOptions(opts...)
 	span := &noopSpan{