tracer.go
func (r SpanReference) Apply(o *StartSpanOptions) {
	if r.ReferencedContext != nil {
		o.References = append(o.References, r)
	}
}
func (r SpanReference) Apply(o *StartSpanOptions) {
	if r.ReferencedContext != nil {
		o.References = append(o.References, r)
	}
}
func ( r SpanReference ) Apply ( o * StartSpanOptions ) { if r . ReferencedContext != nil { o . References = append ( o . References , r ) } }
// Apply satisfies the StartSpanOption interface.
Apply satisfies the StartSpanOption interface .